Skin Terminology/Diseases Flashcards
1
Q
Papule
A
- a small pimple or swelling on the skin, often forming part of a rash
- can be a primary lesion resulting from a flea bite - developing as a direct consequence of disease process
- solid palpable skin elevation less than 1cm in diameter
EX: Canine FAD (crusted papules)
2
Q
secondary lesion
A
- evolve from a primary lesion ot are caused by the patient (aka self trauma)
- selt trauma in veterinary patients may obscure the primary lesions
- secondary bacterial infection may present with primary lesions
3
Q
Panniculus Adiposus
A
- vascular and nerve supply under the layer of the dermis
(generally find sweat glands in this area as well)
- The panniculus adiposus is the fatty layer of the subcutaneous tissues, superficial to a deeper vestigial layer of muscle, the panniculus carnosus. It includes structures that are considered fascia by some sources but not by others
4
Q
the Epidermal Layer
(5 layers)
A
stratified squamous keratinizing epithelium with proliferation, differentiation, desquamation
happens in hair follicle as well - down to the insertion of the sebaceous gland duct - can get notable disruptions
shows there may be a foliclur keratinization or cornification (final stage of keratinization) defect going on
5
Q
Cutaneous Basophil Hypersensitivity
A
- Cutaneous basophil hypersensitivity is a distinct form of hypersensitivity reaction with a delayed-time course that is different from both the classic delayed-type hypersensitivity reaction and immediate hypersensitivity reaction.
- It occurs in humans, guinea pigs, and other animals.
- It may be induced by sensitization with a variety of antigens (viruses, allografts, parasites, fungal antigens, etc.) in incomplete Freund’s adjuvant and elicited by skin testing 7 days later with the specific antigens.
- The cutaneous reaction in basophil hypersensitivity is characterized clinically by less indurated (hardened) erythema than in classic delayed hypersensitivity, and microscopically by numerous basophils in the papillary dermis.
- The reaction is mediated by both T- and B-lymphocytes.
6
Q
Basophils
A
- Basophils appear in many specific kinds of inflammatory reactions, particularly those that cause allergic symptoms.
- Basophils contain anticoagulant heparin, which prevents blood from clotting too quickly.
- They also contain the vasodilator histamine, which promotes blood flow to tissues.
7
Q
Primary lesion
A
If Foot and Mouth replicates in horse epidermis–> may lead to primary lesion in pigs and ruminants
- staphylococcal infection creating pustular lesion in the hair follicle
- a secondary lesion can have its own primary infections - staphylococcus taking advantage of allergy
8
Q
Wheals
A
- you know as they “pit” upon the application of pressure- may get some with traumatic pericarditis
- so it is different to firm nodules or plaques
- YOU GET WHEALS FROM PENICILLIN = hives (urticaria)
- Urticaria (hives) is a vascular reaction of the skin marked by the transient appearance of smooth, slightly elevated papules or plaques (wheals) that are erythematous and that are often attended by severe pruritus. Individual lesions resolve without scarring in several hours
- Horses–> present with wheals more commonly as a species (dogs as well) –> horses are not generally pruritic!
- A skin wheal is a patch on the skin that is elevated, discolored, changes shape, and often itches (+/-). It can be due to an insect bite, an adverse reaction to something that touched your skin, eczema, or another small puncture wound you experienced. You may have also heard a skin wheal referred to as a ‘welt’ or a ‘hive.
- In some animals, serum oozes from the wheals matting the hair coat
9
Q
Angioedema
A
- extensive type wheal
- angioedema is a localized or generalized area of extensive deep dermal and subcutaneous oedema
- affecting the whole body region –> vaccine reactions or maybe (may get dogs swelling up around the head after routine vaccine)
- in comparison, the oedema involves the deep dermis and subcutis where in urticaria it involves only the superficial dermis
- both involve type I and type III hypersensitivities
- pruritis is not always present, especially in the horse
10
Q
Urticaria
A
- Urticaria, also known as hives, is an outbreak of swollen, pale red bumps or plaques (wheals) on the skin that appear suddenly (involving the superficial dermis) – either as a result of the body’s reaction to certain allergens, or for unknown reasons.
- Hives usually cause itching, but may also burn or sting
- a unique form has been described in Jersey and Guernsey cattle bc of a type I hypersensitivity to casein (slow digesting protein) in their milk
- Urticarial lesions are wheals that typically arise suddenly and remain a few hours although chronic urticaria has been noted (lasting weeks to months)
11
Q
macule
A
an area of skin discoloration
12
Q
pustules
A
- A pustule is a bulging patch of skin that’s full of a yellowish fluid called pus
- discrete elevation of the epidermis containing PUS (within or just below epidermis)
- like a plaque with pus
- a mini abscess located near or in the epidermis
- Where as an ABSCESS: is a demarcated dermal/subcutaneous accumulation of pus
13
Q
Vesicle/Bullae
A
Bullae: (Blisters)
Vesicles are circumscribed epidermal elevations in the skin containing clear fluid and less than ½ cm. in diameter. If the lesion has a diameter of greater than ½ cm, it is called a bulla. Vesicles and bullae arise from a cleavage at various levels of the skin
14
Q
Sebaceous Adenitis
A
- Sebaceous adenitis in an uncommon skin disease found in some breeds of dog, and more rarely in cats, rabbits and horses. characterised by an inflammatory response against the dog’s sebaceous glands, which can lead to the destruction of the gland
- targets sebaceous glands and results in alopecia and epidermal and follicular hyperkeratosis
- useful to take a biopsy sample in suspected cases and then have disease confirmed by histopath
- In standard poodles, sebaceous adenitis is definitely a recessive genetic trait
15
Q
Hyperkeratosis
A
abnormal thickening of the outer layer of the skin
- increase in the stratum corneum layer
16
Q
A
- Hair follicles destroyed by fibrosis - where there should be a hair follicle is just collagen
- Could see cytotoxic lymphocytes are now seen attacking the hair follicles in this
- Can now think of drugs that would block lymphocytes mediated autoimmune disease - cyclosporine
- But some owner refuse due to the $$ and dog not suffering from itchy
17
Q
A
- Hair follicles on normal histopathology
18
Q
Examples of diseases that involve different areas of the skin:
- Dermis
- Panniculus (subcutis, hypodermis)
- Epidermis
- Hair Follicles
A
**note: panniculitis, not hepatitis
also in hair follicles: Demodecosis
19
Q
Puppy Strangles
(juvenile cellulitis)
A
- DERMAL DISEASE
- Puppy strangles, or juvenile cellulitis, is a nodular and pustular skin disorder that affects puppies. It usually occurs between the ages of three weeks and four months, and is rarely seen in adult dogs.
- The face, pinnae (outer part of the ear), and salivary lymph nodes are the most common sites to be affected. The cause of this condition is unknown, but there are breeds that have been shown to be predisposed to it, including golden retrievers, dachshunds, and Gordon setters
Clinical Signs
- Acutely (sudden and severe) swollen face – especially the eyelids, lips, and muzzle
- Salivary gland lymphadenopathy: a disease process affecting a lymph node or multiple lymph nodes
- Marked pustular and oozing skin disease, which frequently fistulates (develops into a hollow passage); develops within 24–48 hours
- Pustular ear infection
- Lesions often become crusted
20
Q
Sterile Nodular Palliculitis
A
- Panniculitis is a rare condition in which the layer of fat under the skin, which provides warmth, protection and energy to the body, becomes inflamed.
- While it may be caused by an infection with bacteria, fungi or other organisms, sterile nodular panniculitis is a descriptive term for an inflammation of the fat cells that does not involve infectious agents. In most cases, the exact cause is not known.
- The inflammation results in bumps on the skin surface that can be soft or firm, and are sometimes painful.
- The bumps can rupture, releasing an oily discharge that may be clear, yellow-brown or bloody.
- Most pets with sterile nodular panniculitis are treated with drugs designed to modify the immune system, such as steroids, but Vitamin E may also be helpful
21
Q
Patterns of Inflammation in the Skin
(5)
A
22
Q
Hyperepidermis
A
- increase in the stratum spinosum layer
- epidermal living layers thicken
- may be a protective response by the body to a noxious stimulant from outside
- also as an accidental consequence of a dermal disease triggering cytokines and inflammatory mediators trigerring the basal keratinocytes to increase the proliferative rate
- may see both hyperkeratosis and hyperepidermis in a chronically allergic animal
23
Q
A
- hyperplasia more regular
- hyperkeratosis is quite marked
- CLINICAL EQUIVOLENT: SCALING
- scale = an accumulation of loose fragments in the stratum corneum
- Migration of lymphocytes into the epidermis (lymphocyte exocytosis) is common - as seen here
- can also see in this periodic acid–Schiff (PAS) stain that there is some fungal hyphae - Dermatophytosis (ringworm)
24
Q
Scaling
A
- accumulation of loose cornified fragments from the stratum corneum
25
Follicular Cast
* when scaling then occurs in the **hair follicle infundibulum**
* accumulation of keratinous debris around hari shaft
* indicates issue with the keratinization process around the hair shaft --\> ex: **Demodecosis**
* Most common cause of that would be demodicosis
And then next cause: sebaceous adenitis
* **Must be doing skin scrapings and hair plucks**
26
Comedo
* dilated hair follicles plugged with keratinous and sebaceous debris
* **Black heads**
* May indicate **demodex**, an **endocrinopathy** (hyperthyroidism, hyperadrenocorticism) or a **primary** **kertinisation defect**
27
* histology of **comedo**
* HF packed with keratinous, sebaceous and scaley material
* think **_DEMODECOSIS!_**
* but others are endocrinopathies (hyperthyroid, cushings - middle age/older) - **cycle arrest --\> all the hair is stuck in the telogen phase in arrest as well as the scaling process is distorted by the disease as well**
* or primary keratinization defect - little young spaniel is producing shit loads of scales - get comedos, scaling and follicular casting in some cases (certain breeds at young age or immunosurpressed)
28
Perivascular Dermatitis
**classic stereotypic dermatitis reaction**
**-hyperplastic superficial perivascular dermatitis**
-vessels are dialted, cuff of inflammatory cells
CUFF: recruited leukocytes around BV's
epidermis is thickened due to the cytokines and inflammatory mediators released
**ex: malassezia**
* **make sure to know if it is just superficial or deep plexus and what cell types are present!** -position of inflammatory cells depends on the pathogen (yeast--\> more towards epidermis, food allergy --\> lower as well as superficial)
* is the challenge from the outside or systemically??
* **fleas or sarcoptic mange**: may see more **eosinophils** near epidermis
* **staphylococcal infection**: neutrophils may be more dominant
* **Histo is not pathognomonic**
* This usually includes epidermal hyperplasia! stratum spinosum
29
Cutaneous Lymphoma
* The **_most common tumors in dogs_** are **malignant lymphomas**, which is a condition also defined as a lymphosarcoma. These types of malignancy generate within the lymphoid tissues of the dog, such as the spleen, bone marrow, or lymph nodes. They can occur in any of the bodily tissues (like skin)
* Cutaneous lymphoma is a type of skin cancer that occurs within **abnormal T-cells of the dog**
* **may show as red, itchy skin--\> in any case you may suspect for an animal, send off pathology**
* where as in other situations this type of presentation may not be beneficial
* Cutaneous lymphoma, in the advanced stages, begins to affect the peripheral blood and the internal organs.
30
Plaques
* sometimes papules can coalesce to form **plaques**
* **larger flat topped elevation cuased by the extension of papules (aural plaque)**
* **aural plaque -** viral disease process (papilloma) --\> transmitted by biting flies in most theories (BPV-1)
31
pustule within the epidermis
32
Intraepidermal Pustular Dermatitis
| (eosinophilic vs. neutrophilic)
* 99.9% of neutrophilic will be Staphylococcus pyoderma
33
epidermal collarette
* evolution of a pustule into **epidermal collarette (secondary lesion)**
* expanding ring like erythematous lesions with peeling edges, they are the footprints of **pustules** (primary lesions)
* e.g. **bacterial infection (Staph)**
* **THIS IS ONE OF THE MAIN CAHRACTERISTICS OF SUPERFICIAL PYODERMAS - collarettes in large numbers --\> by _Staphylococcal infection_**
34
Erosion
* break in the continuity of the epidermis but the underlying BM remains intact
* heals because you still have your basal keratinocytes intact
35
Ulceration
* unlike erosion, goes right through
* break in the continuity of the epidermis where the dermis is exposed
* pic: cutaneous lymphoma affecting the paws of a dog creating ulcers
36
Nikolsky sign
* The sign is present when slight rubbing of the skin results in exfoliation of the outermost layer
* where you can strip the epidermis off the underlying epidermis
* **tells you that the disease is targeting the dermal/epidermal jxn**
* **may even be from an adverse drug reaction**
37
Folliculitis
* Inflammation of the hair follicle
* perifolliclitis/luminal folliculitis/ (bulbitis/mural)
* **Powerful pattern**! : in dogs, usualy reflects pyoderma, demodecosis or dermatophytosis
38
Furunculosis
* inflammation and DESTRUCTION of hair follicle
* **ex: deep pyoderma, anal furunculosis (GSD's, also known as perianal fistula, part of GIT strand)**
**where as:**
* **Non-inflammatory alopecia**: Alopecic disease with endocrinopathy --\> Telogen hair follicles with scaling
But **no inflammation! (different to furunculosis)**
39
Crust
* accumulation of exudate (dead cells/dried serum) on skin surface
* site of **previous active inflammation, epidermal degeneration, pustule, etc.**
40
Panniculitis
* **Panniculitis** is a group of diseases whose hallmark is inflammation of subcutaneous adipose tissue (the fatty layer under the skin – panniculus adiposus). Symptoms include tender skin nodules, and systemic signs such as weight loss and fatigue.
* **Inflammation of subcutaneous fat and connective tissue**
* e.g. budding yeast organisms- **Blastomyces (more imp in the US)**
* **Blastomyces dermatitidis** is the causal agent of blastomycosis, an invasive and often serious fungal infection found occasionally in humans and other animals in regions where the fungus is endemic
41
Crusting
* **pemphigus folleaceous**
* need to be careful with scrubbing to get good samples
42
Pemphigus Foliaceous
* **most common and milder form of pemphigus in domestic animals** and has been reported in the horse, goat, dog and cat
* disease develops spontaneously in dogs and cats, as an **adverse reaction to drug therapy**
* autoantibodies recognize the **desmosomal protein, _desmoglein_** , which is predominantly expressed in the upper layers of the epidermis
* **cause cutaenous rather than oral lesions** (different to more severe, involving mucosal layers)
* immunological heterogenous
* gross lesions similar in all species: transient vesicles that rapidly become pustules which can be localized to areas of the skin (nose, pinnae, periocular skin, paw pads, claw beds, and coronary bands in horses)
* pustules quickly rupture as they are fragile --\> leads to secondary crusts, scales, alopecia and superficial erosions
43
Top Causes of Pruritic Skin Disease in **Dog**
(parasitic, microbial, hypersensitivity)
* **Parasitic: scabies**, cheyletiella (surface mites), Burrowing mites (Sarcoptes), Trombicula (Harvest Mites - sometimes), maybe follicular mites (demodex) - but not as itchy
* **Microbial:** Staph Pyoderma, Malassezia
* **Hypersensitivity:** FAD, Atopic Dermaititis, Food Hypersensitivity
44
Top Causes of Pruritic Skin Disease in **Cats**
(Parasitic, Microbial, Hypersensitivity)
* **Parasitic:** Cheyletiella, other mites
* **Microbial:** Bacterial, Malassezia, Dermatophytosis
* **Hypersensitivity:** FAD, 'Atopic Dermatitis', Food Hypersensitivity, _Eosinophilic Plaques_
**\*\*Cats are a lot less likely to get bacterial or fungal secondary infection when they have allergic skin disease compared to dogs**
45
Top Causes of pruritic skin disease: **Horse**
**Parasitic: Chorioptes** (Choriptes bovis) , other mites
**Microbial:** **Staph infection,** Dermatophilus (gram +, "mud fever"), Dermatophytosis
**Hypersensitivity:** Insect bite hypersensitivity (in horses--\> **cullicoides = biting midges**), 'atopic dermatitis', food hypersensitivity?
46
Parasitic Diseases
## Footnote
**Pruritis**
* Surface mites (e.g. Cheyletiella)
* Burrowing Mites (e.g. Sarcoptes)
* Trombicula (harvest mites)
* Demodex - less itchy
47
Microbial Infection/Overgrowth
## Footnote
**Pruritis**
* Staphylococci (commensal)
* Malassezia (commensal)
* Dermatophytes - not typically as itchy
48
Hypersensitivity Disorders
## Footnote
**Pruritis**
* Flea Bite Hypersensitivity
* Atopic Dermatitis
* Food Hypersensitivity
* (contact dermatitis)
49
Less Common pruritic skin diseases
* **Cornification/metabolic disorders**
* **Neoplasia** - epitheliotropic lymphoma/mast cell tumor
* **Drug Eruption**
## Footnote
**\*\* note: you may have more than 1 disease at once!**
50
Priority Dx's to rule out with pruritic disease presentation
(4)
51
Is there anywhere else self trauma is occuring
Top: around muzzle, groin, tail, feet --\> fits with certain types of **allergic skin disease**
Bottom: elbows, chewing hocks, licking around ventrum--\> **much more typical of scabies**
Help prioritize likelihood!
52
Deep and Superficial Skin Scrapings
53
Cytology
| (4 techniques)
54
* bacterial folliculitis!
* -cure to rid of itch and then work on keeping it away
55
Dermatophytosis Epidemiology
| (who does it affect more commonly?)
56
Conidium
**Conidium**, a type of **asexual reproductive spore** of fungi(kingdom Fungi) usually produced at the tip or side of hyphae (filaments that make up the body of a typicalfungus) or on special spore-producing structures called conidiophores.
* **The spores detach when mature**
* **ex: dermatophytosis pathogenesis--\>** conidia adhere to corneocytes from one infected squame of an individual to as susceptible squame of another
57
Dermatophytosis Pathogenesis
| (5 steps)
58
trichophyton verrucosum
* Pretty well demarcated
* Green, thick scales of crust
* Housed cattle
* Contamination of face, head and neck
* Can be extensive
* **important in cattle :** may aso affect dogs, sheep, horses and people
59
Trichophyton equinum
* Similar to bovine lesions but these are a lot less crusty
* Stable situation allows for a lot of transverse spread
60
Expanding Ring like lesions in the dog...
* **most likely staphylococcal folliculitis!**
* If it looks like ringworm on a dog, probably is not
* need to get samples to know!
* CS's: **alopecia, circular lesions, crust, erythema, annular lesions with scaling, possible nodular lesions**
* **there is variability in presentation though!**
* also may see them easier when clipped! like this cat (ring with inflmmation and hematogenous regions)
61
62
* **T. erinacei dermatophytosis (hedgehog)**
* Played with hedgehog
* Inflammatory lesions
Exudation
Symmetry --\> coming from under the skin
Asymmetry--\> lying on the skin
* **could be staph though remember! - need to differentiate and match up Hx**
63
dog presenting with folliculitis/furunculosis on the face
* may be **"sylvatic" dermtophytosis**
* or staph!
* sylvatic --\> contracting from wild animals
64
Which one is which
* Was chasing rodents- JRT's commonly get ***T. mentagrophytes*** **(from rodents)**
* Severe active leading edge of the disease
* Sometimes can get mixed up with pemphigus!! - they have totally different treatments
* in pemphigus foliaceous the nasal plate is affected
65
which one is which
* must do tests to know!
* pyoderma will also be responsible to AB's, but don't want to go ahead treating without ruling out ringworm
66
Dermatophytosis in cats
might just be an Alopecia patch
Not that big of an inflammatory reaction
May not be evoking a strong inflammatory response to "stay quiet" OR the animal cannot amount a response
Protect skin with lesions
* hunting cats may get it from rodents
67
Dermatophyte " Pseudomycetoma"
* Rare: but **Persian cats are more predisposed**
* **deep granulomatous nodular dermal and subcutaneous masses containing distorted fungal hyphae**
* fungus drive into subcutanoeus and fat
* mycetoma--\> nodular lesion with sinus tracts and **tissue grains**
* infectious granuloma
* **Feline dermatophytic mycetomas (pseudomycetoma)** are uncommon deep dermal and subcutaneous fungal infections caused by dermatophytes
* characteristic triad of nodular swelling, draining sinuses, and grains in tissue
* The grains are micro-aggregates of the causative organism. Causative agents in mycetomas **may be bacterial or fungal**. In true fungal mycetomas (eumycetomas)
* **The disease as seen in cats is almost exclusively caused by Microsporum canis**, a unique form of dermatophytosis, with the majority of cases described in **_Persian cats_**, suggesting a genetically programmed selective immunodeficiency
68
Dermatophytosis: Diagnosing
If you take a hair pluck:
## Footnote
May get hair pluck with **microsporum dermatophytosis**
Filamentous hyphae in the hair shaft
Has gotten into the hair shaft and has produced an arthrospore outside the hair shaft
-might see branching, not easy to find though!
**Wood's Lamp:** Only good for M. canis!
**Maximum result from microscopy:** will only find hyphae or spores in about half the cases
-can do light microscopy if you have it to look for hyphae and spores
**Note:** the fungi tend to die in areas of inflammation in the center of lesions but are viable at the periphery
69
Pathogenic Genera of Dermatophytoses
| (3)
* **Epidermophyton -** adapted to humans (anthropophilic) and rarely infects animals
* **Microsporum**
* **Trichophyton**
\*all are adapted to digest keratinous debris
more contagious than other fungal infections!
dermtophytosis is the most important cutaneous superficial mycosis
* common to both human beings and animals, especially cats
* dermatophytes are able to colonize the cornified structures (hair, claws) and the stratum corneum and cause disease without ever entering the living tissue
* young animals and hot environments, or immunosuppression
70
zoophilic dermatophytes
* *Microsporum canis* and *Trichophyton mentagrophytes*
* primary animal pathogens but can infect human beings
* M.canis is well adapted to long hair breed cats
71
Breeds predisposed to *M. Canis*
* Perisan cats
* Himalayan cats
* Yorkshire Terriers
* **source of an M.canis infection is usually an infected cat -ASYMPTOMATIC CARRIER**
* **most common cause of dermatophytosis in dogs and cats -** also associated with equine infections
72
*T. mentagrophytes*
* acquired by contact with reservoir hosts **(rodents!)**
* find in JRT's
* 2nd most common cause of dermatophytosis in the dog in the UK
* **hunting dogs and cats most commonly affected**
73
*Microsporum gypseum*
* Geophilic dermatophyte
* occur in the soil as saprophytes but under favorable conditions can infect humans and animals if the integrity of the skin is broken or host immune system is compromised
* **dogs more often affected than cats**
74
Arthrospores
* typical infective portion of the organism (dermatophytes)
* form by segmentation and fragmentation of fngal hyphae
* dhere strongly to keratin and germinate witin hours of contact- therefore the **infection of the hair shaft does not progress below the zone where cornification occurs**
* dermatophytes invade cornified tissues by producing proteolytic enzymes **(keratinase, elastase, collegenase)**
* The products elaborated by the dermatophytes cause dermal irritation and damage to the epidermis
* resulting **epidermal hyperplasia** (hyperkeratosis, parakeratosis, and acanthosis) and dermal inflammation
* Inflammaotry cells arrive via the superficial vessels **(superficial perivascular dermatitis)**
* **get foliculitits and furunculosis as well** - which bacterial infection increases the severity of
75
Onychomycosis
* **Onychomycosis**, also known as tinea unguium, is a fungal infection of the nail
* discolored, malformed, friable, broken or sloughed claws
76
*microsporum periscolor*
* zoophilic dermatophyte which results in **scaling without hair loss**
* which is unusual in Dermatophytosis as hair shaft invasion is part of the patho
* but M. periscolor only invades the surface of the skin and lacks enzyme properties for hair invasion
77
* **Dermatocyte 'pseudomycetoma'**
* mainly Persian Cats/MC
* hair follicle rupture can --\> infection deep dermis/subcutis by ***M.canis --\>*** granulomatous dermatitis & panniculitis --\> large nodular inflammatory lesion
78
Most sensitive test for dermatophytosis if done properly
* **CULTURE**
* sabourauds dextrose agar + cycloheximide + chloramphenicol, **incubate for up to 4 weeks -con**
* **slow process and disease is rather contagious!!**
* May see macroconidium (which is the spore stage that is never produced on the skin)
* **There are also in house cultures** for dermatophytes (SDA + phenol red indicator)
* **skin biopsies may be helpful in some cases**
79
Treatment for Dermatophytosis
* may resolve as a consequence of adaptive immunity!
* NO STEROID TREATMENT
* but it is a zoonotic disease so do not await resolution in SA
* _clipping and topical therapy:_
* **Enilconazole (an imidazole) -** dogs, cattle, horses
* **Miconazole - chlorohexidine combo (malaseb shampoo) or lime-sulphur sol'n in** cats
_Systemic Therapy_
* **itraconzole (itrafungol)** -licensed for cat
* **Bovillis ringvac** - cattle --\> **live attenuated *T. verocosum* vaccine**
80
Dermatophyte Test Medium
## Footnote
**which is the positive dermtophyte sample?**
-low temperatre may delay the speed of the color change
81
Dermatophyte Test Medium Pitfalls
82
* Skin biopsies can be useful
* **Clear translucent fungal hyphae**
* **Dermatophytosis**
* arthrospores around the hair follicle in pic below
83
Targets of Antifungal Therapy in **Malassezia** and **Dermatophytosis**
84
Malassezia Dermatitis
* Malassezia infections are seen most commonly in dogs (and cats at lesser rate) - horses sometimes
* usually caused by ***Malassezia pachydermatis* (*pityrosporum canis*)**
* a lipophilic, but non-lipid dependent yeast tht is considered to be a commensal organism in dogs and cats and can be isolated from the normal external canal, skin, anal sacs and mucosal surfaces
85
***Malassezia pachydermatis***
* species of improtance in dogs and cats
* **unique in the genus as it will grow on Sabouraud Dextrose Agar** ( it IS actually lipid dependent as well, but grows on regular media unlike **M. furfur)**
* lives in the stratum corneum and becomes a pathogen when predisposing factors alter host cutaenous microenvironment, epidermal barrier or immune system --\> including **increased heat and humidity, alterations in the amount of composition of surface lipids in response to changes in hormones, cornification disorders, nutritional disturbances and presence of allergic skin disease**
* can infect the ear canal - **Malassezia otitis**
* or skin surface more generally - **Malassezia dermatitis**
86
Breeds Predisposed to infection by **Malassezia**
* Basset Hounds
* Westies
* cocker spaniels
* cats: sphynx, Devon rex
* **more common in dogs than cats, often found in dogs with concurrent dermatoses (especially hypersensitivity dermatitis or staphylococcal bacterial folliculitis)**
87
Gross appearance of lesions: **Malassezia**
* eryhtematous
* alopecic
* often licenified
* may have hyperpigmentation
* lesion surface is often greay and may be malodorous **(yeast makes it stink!)**
* sometimes symmetrical in presentation
* affected claws and hairs may have red/brown discoloration
* **Lesions are variably pruritic** - bc *M. pachydermatis* does not invade below the stratum corneum - it is likely that animals associated with Malassezia dermatitis have a hypersensitivity reaction to yeast products or antigens - but animals can have an **intense pruritis involved!!**
* cats: dark, greasy brown exudate (Likely the fungus itself and the sebaceous exudate mixed together)
on the claws, claw fold, palmar and plantar interdigital areas, axillae , groin and sometime ears . **generalized greasy dermatitis**
88
Diagnosing Malassezia
* Malassezia spp. can be lost during tissue processsing
* **cytologic evaluation** is often more reliable to detect and enumerate yeasts
* culture is rarely needed
* counts on cytology may or may not be high --\> **initiate trial therapy :** sometimes treating the yeast will make the animal better and often it wont
* may need to go back and sample again or research another reason for animals dermatitis
* it is another disease of the **STRATUM CORNEUM**
89
* *Malassezia Pachydermatitis*
* spiraling unique to the genus
90
* **Malassezia otitis**
* erythamato-seruminous otitis externa
* red and waxy ears --\> Malasezzia overgrowth
91
Malassezia and Bacteria
* may affect eachothers growth and regulation in the stratum corneoum
* prevent overgrowth of eachother
* might modify each others metabolism and virulence
92
Scaling Disorders can favor Malassezia as well
ex: bulldog populations genetically prediposed
**FOLDS IS ALSO A BIG COMPONENT: warm and moist**
**-will often have Malassezia, bacteria or both living in folds (even mammary folds and ear canals)**
93
Cats and Malassezia
* **Cats are a bit different!**
* can have Malassezia as a consequence of dermatitis
* But much less common than in dogs
* Black gunge around toe edge around claw folds
* Sphinx cats and Devon Rex (but not cornish rex weirdly!)
* Older cats with serious internal disease (pancreatic paraneoplastic alopecia) --\> ventral hair loss with shiny skin bc of thin stratum corneum with ancreatic carcinoma
* Get secondary malessezia complicating this disease triggered by internal problem
94
Thymoma-Associated Exfoliative Dermatitis
* scaling disorder as a paraneoplastic sign
* indicative of Malassezia overgrowth
* controlling the underlying trigger (thymoma) and the Malassezia populations wen back to normal
* these kinds of conditions are more seen in the cat than the dog
95
Predisposing Factors favoring the yeast
(7)
* about half these cases have underlying allergy! - so treating yeast may not solve the pruritis
* need to treat that to then possibly discover other possible diseases present
96
Clinical Signs in Dogs
## Footnote
**Malassezia dermatitis**
**(7)**
* **Paronychia**: crusting, discolored claw (infection of the nail)
- especially cats but also in dogs too
* **Frenzied Facial Pruritis**: cheilitis/muzzle erythema
97
* Malassezia paronychia
98
Malassezia dermatitis: frenzied muzzle pruritis
* Can sometime be confused for neurological disease
Trying to scratch the muzzle
**It is malessezia!**
99
nil clinical and nil mycological outcome from therapeutic trial of Malassezia
* suspect MD
review owner compliance
* extend/intensify treatment
* review compliance
* change treatment - **there is antifungal resistance to some Malassezia!**
100
* Malassezia on cytology
* tape strip and DifQuik
* can also do Quanititative culture plates in practice: stick right on lesions and grow from there
* **CupScrub is the gold standard, but tape strip is most used**
101
Best Media to grow Malassezia on
* **modified DIxon's agar**
* target M. pachydermatis
* dogs: sabarouds Dextrose Agar as an alternative with Tween supplemented (extra source of lipid)
* cats:have other 5 species of lipophilic kind need more exacting temperatures (not higher than 34C)
* dogs --\> 3 day incubation
* cats --\> 7 days
102
* green staining showing Malassezia
103
Systemic Therapy for dogs with Malassezia
104
Treatment for Deep Pyoderma
105
Intertrigo
**Intertrigo** (in-tur-TRY-go) is inflammation caused by skin-to-skin friction, most often in warm, moist areas of the body, such as the groin, between folds of skin on the abdomen, under the arms or between toes
* **Often surface pyoderma**
* **associated skin diseases such as atopic dermatitis may complicate/be the initital trigger**
106
Puppy Impetigo
| (juvenile pustular dermatitis)
* **Puppy impetigo** (pyoderma, juvenile pustular dermatitis) is an infection caused by bacteria such as **staphylococcus**, also called staph infection.
* **presents as interfollicular pustules**
* **Tx: topical antibacterial therapy -** prognosis: good, rarely recurrent
* There are many different types of staphylococcus strains which can affect dogs as well as people and may be passed back and forth.
* Highly contagious, it is also resistant to antibiotics rendering it hard to eliminate
* **often part of superficial pyoderma**
* **may require topical +/- systemic therapy**
* **Usually S. pseudintermedius**
107
Pyotraumatic Dermatitis
"Hot Spot"
* Disruption of Stratum Corneum and bacterial invasion due to underlying inflammatory or pruritic problem (allergy, otitis, ectoparasites, anal sac disease)
* Often Large breeds (retriever)
* **DO not mistake with pyotraumatic folliculitis/furunculosis** which have **SATELLITE LESIONS - indicating haematogenous spread and _deep pyoderma_**
* In cases of pyotraumatic dermatitis, you also want to give treatment for underlying inflammatory/pruritic problem - **anti - inflammatory & ectoparasite control**
108
Bacterial Overgrowth
* large # of bacteria in the epidermis but **few or no neutrophils**
* marked pruritis, seborrhoea (dandruff), malodour, erythema, alopecia, etc.
* often associated with underlying **allergy dermatitis**
109
Typical Lesions of Superficial Pyoderma
* erythematous macules mature (area of skin discoloration) --\> papules --\> pustules --\> rupture to form epidermal collarettes --\> focal areas of alopecia and pruritis
* usually a range of these lesion types can be seen at once on a patient (long haired)
* In short haired breeds- moth eaten appearance
* **confirm with cytology(neutrophils and cocci present)**
110
Treatment of Superficial Pyoderma
* **treat with topical therapy whenever possible!**
* **Chlorohexidine shampoo 2-3x per week -** effective in 70% of dogs with superficial pyoderma
* Benefits: treat diseased organ directly, safer for own pet, suitable for long term
111
When systemic drugs are needed for superficial pyoderma treatment
(1st tier drugs)
(4)
* **Clindamycin/lincomycin**
* **cephalexin**
* **amoxicillin- clauvulanic acid (efficacy 60-70% for superficial pyoderma)**
* **Potentiated Sulfonamides (TMPS)** - cheap, but can have adverse reactions!
112
Indication for use of systemic antimicrobials after **bacterial culture & sensitivity tests**
## Footnote
**2nd tier drugs**
****use if the first tier drugs are not appropriate for the bacteria found after culture &sensitivity
* **Fluoroquinolones**
* **Doxycycline (minocycline)**
* **Cefovecin (convenia) -** 3rd generation cephalosporin
Not licensed for use in the UK: **Chloramphenicol, Rifampicin, Aminoglycosides** (gentamicin, amikacin)
113
**CS's of Deep Pyoderma**
* **Furunculosis** (painful)
* **Interdigital Nodules** (maybe lameness)
* **Acral Lick Dermatitis** - chronic self-trauma --\> plaque formation & ulceration
* **Chin Acne** - Typically Young Dogs, Short-haired breeds, underlying causes varied
* **Bacterial Granuloma -** further tests needed to differentiate from sterile granuloma
114
Tx of Deep Pyoderma
* **Always treat systemically**
* and also treat the underlying cause!
* Always based on **culutre and susceptibility testing**
* while waiting for laboratory report 5-7 days
* **start Tx based on cytology findings ---\>**
* **cocci (likely Staph pseudintermedius) :** cephalexin (1st generation cephalosporin)
* **rods:** consider a fluoroquinolone, likely a more resistant bacteria
* **LONG COURSES OF AB's:** 4-6 weeks at least 2 weeks beyond clinical resolution
* unlike UTI, cannot just measure for resolution of bacteria as the skin is normally full of bacteria
115
Lichenification
* exaggeration of skin markings
* Lichenification is a skin condition that occurs in response to excessive itching or rubbing of the skin and results in thick, leathery patches of skin.
* This occurs because the outer layer of skin naturally thickens with the extra irritation, and it often happens in tandem with eczema or other skin disorders
116
Scale
* an accumulation of **loose cornified fragments** of the **stratum corneum**
* Seborrhoea is a type of scaling
117
Seborrhoea
* literally "**flow of Sebum"**
* vague, clinical **descriptive term** used for animals which present with scaling disorders & varying levels of greasy exudation (does not imply a specific aetiology)
* **Seborrhoea sicca** (=dry)
* **Seborrhoea oleosa** (=oily)
* just tells you that the animal has some form of scaling process occurring
118
Crust
* the presence of a dried exudate (serum/blood/pus) on the skin surface
119
"moving Escalator"
* constant turnover provides protection
* alcceleration of this can be protective in case of noxious stimulus on the skin surface
* Thickening also protects if trauma (e.g. itch)
120
Seborrhoeic Dermatitis
greasy, inflamed skin
* a lot of the time with this description they actually have Malassezia dermatitis
121
Lesion types you may see in scaling disorders
(3)
* surface scale may pack into the infundibulum and onto the hair from surface scale
122
Tachyphylaxis
* rapidly diminishing response to successive doses of a drug, rendering it less effective. The effect is common with drugs acting on the nervous system
* liver metabolizing a drug rapidly
* **Depots of Dexamethasone** can be good for non - pillable cats with allergic skin BUT, **they may metabolize it in the liver rapidly making them less sensitive to the steroids**
* **_more and more injections can lead to more side effects_**
* BUTTTT, overall cats are more resistant to the adverse side effects as they are more resistant - so we need to be a bit more brave with our GC doses while monitoring SE's
* **take care with Ciclosporin (2nd line Tx) in Toxoplasma naiive animals! -check toxoplasma Ab's before treatment**
123
* **Basal Cell tumor/Trichoblastoma**
* Epithelial tumors withoutepidermal or adnexal differentitation
* **Epithelial Tumor - Follicular Tumor type**
* **#1 skin tumor in the cat! (20%) -** With SCC being a close second (15%)
* presentation: pigmented, dome shaped, hairless, MOBILE, maybe ulcerated
* most common around head/neck and shoulders
* may have some melanin and inflammatory cells present
* **There is a malignant form! - Basal Cell Carcinoma**
* low rate of metastasis, take a wide excision --\> may have to end up taking wider margins than an original excision or if the cytology looks malignant, take wider margins initially
124
Elkhound and Keeshonds predisposition
**ICE/IKA**
* **Intracutaneous cornifying epithelioma/ keratocanthoma/infundibular keratinizing acanthoma**
* **Epithelial Tumor - Follicular Tumor Type**
* _MOSTLY YOUNG DOGS_ - rarely cats
* solitary or multicentric --\> see in elkhounds and keeshonds
* Pore and toothpaste like material in the middle of it - **keratin**
* if you get rupture there may be inflammation
* If there are multiple lesions present - maybe try retinoids (can be teratogenic though!)
* otherwise, aim for excisional biopsy
125
**Epithelial Tumors :** Hair Follicle Tumours
(5)
* associated with the **hair follicle and adnexa**
* ***most are solitary and benign and can be cured by Sx***
1. Basal Cell Tumours/trichoblastoma **- #1 skin tumor in the cat**
2. ICE/IKA
3. Trichoepithelioma - differentiation to all segments of hair follicle
4. Pilomatricoma - material differentiation: **Kerry Blue Terriers especially**
5. Trichilemmoma
* **remember: these are mostly solitary and cured by surgery!**
126
Epithelial Tumors - Epidermal Tumors
| (3)
* arise **superficially** in the epidermis
1. papillomas
2. Squamous Cell Carcinomas (SCC) - 15% of all cat skin tumors
3. Multicentric SCC in situ (bowenoid carcinoma) - may be linked to papilloma virus, is not associated with UV damage
127
**Epithelial Tumors -** Tumors of Glandular Origin
(5)
1. **Sebaceous Gland Tumors** - common in dogs, rare in cats
2. **Perianal/hepatoid gland tumors** - modified sebaceous glands in perianal region --\> (Peri-anal adenoma, peri- anal adenocarcinoma)
3. **Sweat Gland Tumors** - Tumors of apocrine (most) or eccrine (rare, footpad) glands --\> Apocrine cysts/adenomas, adenocarcinomas)
4. **Apocrine Gland** - Anal Sac Adenocarcinoma
5. **Ceruminous Gland Tumours (ear)**
128
Mesenchymal Tumors
| (3 types with specific neoplasms)
* ***typically affect SQ tissues (connective/structural tissue origins) rather than the skin itself***
1. Benign Mesenchymal Tumors: lipoma, fibroma and haemangiosarcoma **-Sx is often curative**
2. Malignant/soft tissue sarcomas - we tend to group the malignant tumors in this category (treat similarly) - **EXCEPT:** haemangiosarcoma and Feline Injection Site Sarcoma (ISS)
3. Haemangiosarcoma of skin/SQ - **UV related**
note**- LIPOMA: common, generally easy to excise and remove**
**PNS =** peripheral nerve sheath tumor
129
Sebaceous Gland Tumors
* mostly benigg so excision should be curative!
* but there is a malignant form - **sebaceous adenocarcinoma -** low metastatic/recurrence rate
130
Perianal Adenomas
* **QUITE COMMON! - intact males esp.**
* **ANDROGEN DEPENDENT**
* **breeds:** cockers, English bulldog, samoyed
* **Tx:** castration, excise (delmadinone acetate). castration highly recommended so they dont develop more of them!
* **perianal adenocarcinoma --\> RARE luckily** -also not hormonally driven. low metastatic rate - about 15%
131
Tumors of Glandular Origin
## Footnote
**Perianal/hepatoid gland tumors**
* Perianal adenocarcinoma - would possibly follow up excision with Rx therapy if the margins were incomplete
132
Apocrine vs. Eccrine glands
133
Tumors of Glandular Origin
## Footnote
**Sweat Gland tumors**
**(apocrine and eccrine)**
**(2)**
* **apocrine cysts/adenomas:** common in dogs, less in cats
* **apocrine adenocarcinomas** - more common in older pets and cats, less common in dogs. still a low metastatic rate (less than 6%) so hopefully most Sx is curative!
134
Apocrine Gland - Anal Sac Adenocarcinoma
* can even be the size of a pea in the anal sac!
* may get signs of PU/PD --\> about a quarter of these lead to **paraneoplastic hypercalcemia**
* **Paraneoplastic hypercalcemia or hypercalcemia of malignancy (HM)** is aparaneoplastic syndrome as- sociated with an abnormal elevation of serumcalcium. It is normally associated with the secretion of parathyroid hormone-related protein (PTH-rP) by the neoplasm
* look at ionised calcium for the biologically active fraction
* **Note:** there ARE other malignancies that can cause hypercalcemia! - so rectal exam is crucial on these patients
* most are metastatic at Dx - you REALLY need to stage these before removal!! - by US, Rx or CT scans if possible
* can get distant metastasis but that likely would happen later on
135
Apocrine Gland - Anal Sac Adenocarcinoma
## Footnote
**Treatment**
* this dog has anal sac mass on CT and an enlarged medial LN
* think of local control first as these are generally slow to metastasise
* often these are incompletely resected due to the location
* usually think Sx and then RT in the local area and then down to the LN bed
* multimodal therapy tends to get the best results
136
Medical Therapy for Slow Growing Tumors
(4)
TKI = tyrosine kinase inhibitor
bottom ones --\> other cytotoxic agents that some use
137
Tx of Mesenchymal Tumors
* issue is that they are locally invasive! - **get recurrence**
* **may consider chemotherapy as well for the higher grade tumors - Doxorubicin based**
138
Mesenchymal Tumors
## Footnote
**Haemangiosarcoma of the Skin/SQ**
-poorly pigmented dogs!
SQ ones have increased risk of metastasis! - Sx followed by chemo usually (doxorubicin based)
139
Epitheliotrophic Lymphoma Treatment
* most are partial responses to Lomustine
* they do tend to get secondary infections! - so it is good to use Malaseb or other shampoos to help with hydrating the skin and making them less itchy
140
What is a common toxicity with the use of Lomustine??
also what organ toxicity?
* **_myelosuppression_ (check neutrophil count 7 days after first dose and then prior to each dose)**
* also neutropenia is common
* thrombocytopenia can also occur!
* not really common to see alopecia in animals on chemo bc the hair coat has phases of growth/resting phases. resting phases won't be affected
* **_risk of Liver Toxicity!_** - measure liver enzymes (ALT) prior to each treatment and then recommended to give **SAMe** (a liver supplement) before as well - seems to help to reduce the amount of liver enzymes going up
141
SAMe
| (liver Protection)
* **VET-SAMe** is a nutritional supplement that contains **S-Adenosyl-L-Methionine** to **help support liver health and protection**. It also uses natural plant extracts ginkgo and andrographis to help support cognitive function, increased blood flow, control liver enzymes and help protect the heart
142
Alternative Treatment for Epitheliotrophic Lymphoma
(other than Lomustine and Masitinib)
**4**
* **COP/COAP** -drugs we would commonly use for a more multicentric lymphoma
* Retinoids- **supposed to help the epithelium form more normally** --\> (teratogenic, monitor liver enzymes)
* L-asparaginase (expensive)
* **Maybe Sx or RT if in a localized** form rather than a generalized form!
* RT can be helpful with lesions around the mouth or mucocutaneous junctions
* often epitheliotrophic lymphoma can be missed as it is mistaken for other diseases - could have a few months to 2 year prognosis depending on the treatment
143
Lymphadenitis
* **Lymphadenitis** is the medical term for inflamed and enlarged lymph nodes. It is usually due to an infection. Lymph nodes are filled with white blood cells that help your body fight infections.
* When lymph nodes become infected, it's usually because an infection started somewhere else in your body
144
Medial Iliac and Sublumbar LN's...
* common sites for metastasis of **Apocrine Gland Anal Sac Adenocarcinomas**
* **important to stage these as many are metastatic at the time of Dx**
* also good to image the **spleen, lungs and liver**
145
146
Ideal Treatment of Anal Sac Carcinomas
* Sx and RT seem to have a greater effect over medical therapy
* but all of them together seem to lead to decent prognosis and survival times
147
Alternative Treatments to Anal Sac Carcinomas
(5)
148
Myisasis
* **Myiasis is infection with a fly larva**, usually occurring in tropical and subtropical areas. There are several ways for flies to transmit their larvae to people. Some flies attach their eggs to mosquitoes and wait for mosquitoes to bite people.
* **can cause skin issues and annoyance for horses!**
149
Cutaneous Habronemiasis
* **Cutaneous habronemiasis** is a skin disease of Equidae caused in part by the larvae of the spirurid stomach worms (GIT parasites).
* **disease that is transmitted to horses by flies!**
* When the larvae emerge from flies feeding on preexisting wounds or on moisture of the genitalia or eyes, they migrate into and irritate the tissue, which causes a granulomatous reaction. The lesion becomes chronic, and healing is protracted. Diagnosis is based on finding nonhealing, reddish brown, greasy skin granulomas that contain yellow, calcified material the size of rice grains. Larvae, recognized by spiny knobs on their tails, can sometimes be demonstrated in scrapings of the lesions.
150
Onchocerchiasis
* Onchocerciasis is an infestation of the Onchocerca genus of roundworm, also referred to as neck threadworms.
* **spread by flies from horse to horse!**
* These worms can be around 2.5 to almost 12 inches long in adulthood, and they generally live in the ligament that runs down the nape of the neck, although they have occasionally been found residing in other ligaments as well. When the adult worms release their larvae into the system, they travel to the skin where they cause small, itchy bumps. On rare occasions they may also travel to the eye, causing swelling and pain
151
The most common skin allergy in horses...
**SWEET ITCH (Insect Bitte Hypersensitivity) -** A type of Allergic Dermatitis in horses
* older than 6 months usually
* IgE type I hypersensitivity to *Cullicoides spp.*
* esp. wet fields with little winds
* often seasonal!
* may cuase restlessness and WL
* **tx: repellents** (cypermethrin, flumethrin - watch fish!), **avoidance, anit-inflammatory (CARE - SE's possible incliuding laminitis)**
* **antihistamines** - not shown to be very effective
**Differential Dx:** pinworm (oxyuriasis)
152
Rare parasitic infections in horses (aka not as likely)
* Scabies
* Demodicosis
153
Most common Immune-mediated/Autoimmune Diseases in Horses
(5)
* **Vaculitis (incl. Purpura haemorrhagica) being the most common**
* purpura hemorrhagica is also a subsequent diseaes of Strangles in some horses
* In pemphigus foliaceus - oedema also occurs in the horse
* alopecia areata - focal areas of typically non-inflammatory alopecia
* **usually give GC's as treatment for these diseases**
154
"Cushings" in the horse
## Footnote
**PPID**
**pituitary pars intermedia dysfucntion (PPID)**
* Hirsutism - shaggy long hair coat (60-100%)
* Predisposition to Laminitis (25-82%)
* **hyperhydrosis**: excessive sweating
* Tx: pergolide, Trilostane
155
**horses:** Systemic granulomatous disease/chronic eosinophilic enteritis
## Footnote
**"equine sarcoidosis" - "wasting" disease**
* **grave prognosis:** affecting many systems, but skin is the most obvious!
* skin signs --\> exfoliative dermatitis , may see effects near coronary band
* **Dx**: biopsy of granulomatous lesions or **finding eosinophils throughout organ systems**
156
**Most common nodular disease** in the horse...
(usually a bunch of firm nodules appearing in the saddle area)
- as well as neck/flanks in spring/summer
- not pruritic/painful, tend not to bother the horse
- mineralization in chronic lesions
* **Collagenolytic Granuloma** -sterile cause
* **(eosinophilic granuloma)**
* might be caused by hypersensitivity to insect bites
* **NEED Histopathology and biopsy to confirm this!! -** as there are loads of possible differential Dx's - **will seeeosinophils and changes to the collagen fibers**
* **can look extremely similar to Dermatophilosis**
* **Tx: Leave alone, sx excision, GC's** (usualyl intralesional, but systemic works)
157
Tx and Prognosis of Collagenolytic Granuloma
158
Equine Sarcoids
(differential Dx's)
**6 groups**
159
**Occult Sarcoids**
## Footnote
Flat, circular thickened areas
May also appear as small nodules 2 – 5 mm in diameter
Usually found on the neck, mouth, eyes, and inside of the thighs and upper forelegs
* dermatophytosis
* burns
* trauma
160
Nodular Sarcoid
## Footnote
Firm, raised circular nodules
5 – 20 mm in diameter
Usually in the **sheath/groin area and eyelids**
* fibroma
* melanoma
* collagenolytic
* granuloma
* warble fly cysts
161
Verrucous Sarcoid
## Footnote
Wart-like appearance
Can occur anywhere along face, body, and groin area
* papillomatosis
* chronic sweet itch
* squamous cell carcinoma
162
**Fibroblastic Sarcoid**
## Footnote
Proliferative, fleshy, and ulcerative
Usually along the groin, lower legs, and eyelid
* Granulation tissue
* Botryomycosis
* Habronemiasis
* Neurofibroma
* SCC
163
**Mixed Sarcoid**
## Footnote
This type is more typical of a sarcoid that has been on the horse for a long time, or has experienced some sort of trauma.
mix of other groups
* easy to recognise
* granulation tissue
* habronemiasis
164
**Malevolent Sarcoid**
## Footnote
Appear as multiple nodules
Are locally invasive and occasionally infiltrate the local lymphaticsystem, appearing like cords under the skin
* Lymphangitis
* Glanders
* Lymphosarcoma
* Subcutaenous mycosis
165
Equine Sarcoids
* **A sarcoid is a tumor found on the skin of horses, donkeys, and mules**.
* _It is one of the most common skin neoplasias seen in horses_. It is generally benign and non-life-threatening but can be locally invasive.
* **Sarcoids can have several different appearances and sometimes look like a thickened and bleeding area (ulceration) that may crust over as it heals.**
* Other skin lesions, such as the equine papilloma, can be confused for sarcoids. However, the papilloma will go away on its own over time, while the sarcoid will rarely regress.
* There has been no specific cause identified for sarcoids, **but the bovinepapilloma virus (BPV) is thought to be a potential contributor**. Both **BPV types 1 and 2 have been associated with the formation of sarcoid disease in horses.** Research has yet to determine the method in which the disease is transmitted, but several theories exist - **likely FLIES!**
166
Approach to Lumps
* **FNA and/or excisional biopsy**
* then leading to **Histopathology** and/or macerated tissue culture (**consider whether sterile granuloma/infective granuloma** or **neoplasia**)
167
Effective Tx for Demratophilosis
(3)
(mud-fever)
1. responds **chlorohexidine (topical)**
2. **Sytemic antimicrobials**
3. **KEEP DRY**
168
Effective Tx for Chorioptes on Horses
| (6)
1. clip away excess feathers/hair
2. avoid straw - abrasive, can harbor mites
3. Avermectins (injections) - controversial in the use- not blood sucking
4. Frontline Spray (Fipronil) - **$$$**
5. Lime Sulphur Washes +/- other shampoos
6. Deosect (Zoetis) - cypemethrine: diluted, then sprayed/sponged on (off -label)
169
Important Differential Diagnosis to Mud Fever!
* **Chronic Progressive Lymphoedema**
* does NOT equal chronic pastern dermatitis
* See in **shire, clydesdales, Belgian, German Drafts** -multifactorial with a genetic component
* **starts young** - then progresses
* **thick walled lymphatics, dermal oedema, inflammation, fibrosis, neovascularisation (formation of new BV's), elastin degeneration, arteriosclerosis, fibrosed veins**
* similar to human elephantiasis verrucosa
* **coronary band markedly hyperkeratotic & hyperplastic, poor hoof quality, ergots chestnuts often mishapen**
* complicated by secondary bacterial & parasitic infections
* **management for life if caught early**
* clip and short feathers even though owners hate it!
* Dry env't, exercise to get BF and lymph flow
* **Decongestion Therapy** (manual lymph drainage & compression bandaging)
170
Common **primary and secondary skin** and coat lesions FA
| (parasitic, bacterial, viral, fungal)
**_Primary:_**
* **parasitic:** lice, mites
* **Bacterial:** erysipelas, dermatophilus
* **Viral:** warts, orf
* **Fungal:** ring worm (Dermatophytosis - *Trichophyton verrucosum)*
* ***_Secondary:_**
* **Underlying disease, underlying deificency - Cu deficiency** --\> red coat & "spectacles"
171
**Treatments for ectoparasites of cattle and sheep (& pigs)**
(5)
1. **Macrocyclic Lactones** (clear drench) - e.g. **ivermectins - particularly for mites/lice**
2. **Synthetic pyrethroids** - e.g. cypermethrin, deltramethrin, Dysect pour ons, Crovect, "flectron" ear tags
3. **Organophosphates** - diazinon (only one) --\> dips, unsafe for humans!
4. **Amidines** - e.g. amitraz
5. **Insect Growth Regulators (IGR's)** - cyromazine (Vetrazin pour on)
172
Lice in cattle
* **chewing (bovicola bovis) and sucking (H. eurysternus) lice**
* Main issue: **pruritis!** anemia possible if REALLY bad/heavy infestation, **hair loss due to rubbing**
* **young animals**
* **poor conditions/intercurrent disease =** predisposing factors
* may affect growth rate, but overall small effect on productivity
* blemishes could decrease leather values
* **Numbers increase in cool months!** - peak early spring
* Lice infestation in cattle - lice grow during winter in the shed, and then turn them out and _sun can be just as effective of a treatment as insecticides_
* **MOST COMMON IN HOUSED CATTLE**
* Dx: **easily visible to maked eye!**
* **Tx:** if needed due to welfare, best to treat in Autumn, when no lice are visible due to lowered numbers
1. Macrocytic Lactones (b.bovis)
2. pour on pyrethroids - deltamethrin or cypermethrin
173
Scrapie
* Scrapie - disease of the sheep, may lead to an itchy pruritic sheep
* If you suspect this on a farm you must report to the APHA!
* Scrapie is a fatal, degenerative disease that affects the nervous systems of sheep and goats. It is one of several transmissible spongiform encephalopathies (TSEs), which also includes bovine spongiform encephalopathy (BSE or "mad cow disease"), Creutzfeldt-Jakob disease (CJD) in humans, and chronic wasting disease in deer. Like other spongiform encephalopathies, the cause of scrapie is unknown, but is thought to be caused by an infectious misfolded protein called a prion.
* has been known since 1732, and does not appear to be transmissible to humans
174
Mites in Cattle
| (4 types)
***_more important in terms of clinical disease than lice!_***
**IMPORTANT:** *sarcoptes scabiei, chrioptes bovis, demodex bovis, psoroptes ovis*
1. **Chorioptic Mange**- common --\> **tail mange**, non -burrowing, not severe, v. common in housed cattle
2. **Sarcoptic Mange** - not as common, head & tail mange, mostly housed cattle, **can be severe and acute in onse**t, transmission by direct contact (survive on fomites) - can use ML's to treat as they are burrowing mites!
3. **Psoroptic Mange** - non burrowing, fairly rare in cattle, affects the flanks! - significant lesions --\> injectable ML's/permethrin Tx
4. **Demodectic Mange -** common but rarely diagnosed- more of a problem for hide damage! no pruritis, little hair loss
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*T.verrucosum*
* ringworm in cattle causing Dermatophytosis
* focal pathces of thick grey scale
* **self limiting - 1-3 months!**
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Lice in Sheep
## Footnote
*Bovicola ovis (sheep body louse), Linggnathus ovillus*
* can get dual infestation of lice and mites on some farms
* **severe fleece derangement**
* Rubbing, biting wool - more important in Merino type breeds
* numbers high in long wool, decrease dramatically at shearing and with UV radiation
* higher incidence in UK since dipping stopped
* **Tx:** shear, insecticides, pour on (cypermethrin, deltamethrin)
* or saturation dip!
* Pour ons are considered not fully effective in full fleeced animals
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Sheep Mites
Important: *sarcoptes scabiei, demodex ovis, psorobia ovis, chorioptes bovis, **psoroptes ovis***
* **Psoroptic Mange- "SHEEP SCAB"**
* pustules and then spreading of moist lesions
* fleece becomes matted
* severe pruritis, can become extensive
* sheep may become thin and die - risk of hypothermia and death
* **multiples rapidly over winter** and then may become latent over summer
* If a mite drops off, is infectious for the first 17 days after falling into env't, can affect another
* pasture, fences, buildings are a source for re-infection for up to **15 days**
* **not all sheep show infections - there is a carrier status!**
* **Best Tx**: ML's (but $$) - Doramectin, Ivermectin, Moxidectin (clear drenches) --\> affects external and internal parasites so worming will be affected! - **Will increase the resistance of these roundworms to the macrocytic lactones used!!**
- will also increase resistance in the mites themselvves!
- has been a good amount of dose failures
- they have already **shown resistance to ivermectin**
* If they are ridding of them at the time of infection, may be just best to send infected ones to the abbatoir
* **other Tx**: plunge dips (watch for post dipping lameness- e. rhusopathiae), Organophosphates --\> (AChE inhibition) - highly toxic to all species (only Diazinon approved in the UK)
*
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E. rhusopathiae
**Erysipelothrix rhusiopathiae** is a Gram-positive, catalase-negative, rod-shaped, non-spore-forming, nonacid-fast, nonmotile bacterium. Distributed worldwide, E. rhusiopathiae is primarily considered an animal pathogen, causing the disease known as erysipelas that may affect a wide range of animals
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Blowfly Strike
| (Cutaneous Myasis)
* **V. important disease in sheep! - causes much distress and a slow death**
* survivors lose productivity and it is $$ to try and prevent
* **Predilection sites**: head (base of horns), Breech (ass), prepuce, body, wounds
* Will see these one nibble at their back end rather than scratching
* primary flies lay eggs in wool/inflamed skin
* larvae feed onsurface and cause extensive skin damage --\> toxemia due to skin necrosis and absorption of bacterial toxins
* secondary and then tertiary flies may then invade
* **Tx: clip, clean tissue, remove maggots, apply insecticide, and supportive therapy in extreme cases**
* **Prevention:** tail docking of lambs assists in reducing "breech strike"
* **-Cyromazine (Vetrazin)/Cypermethrin**
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dermatophilus in sheep
* **"LUMPY WOOL" in sheep**
* **Actinomycete bacteria!! - filamentous**
* see in sheep, camelids, goats, pigs and rarely cattle
* **produces crusts of varying thickness** on wooled and/or haired skin
* tends to follow WET WHEATHER
* **Dx: history, CS's, smears from scabs with DiffQuik --\>** look for rows of Gram positive cocci and railroad track formation (filaments)
* **Tx**: remove animals from wet weather, chlorohexidine scrubs (topical Tx) , give AB's (Penicillin - 5days, Oxytetracycline - 1 dose)
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Regulation of Hair Growth
| (4 types)
* **Nutrition -** malnutrition ( can decrease hair growth), metabolic diseases - body may sacrifice hair for protein reserves
* **Central/systemic**- hormones, thyroid hormone, glucocorticoids, sex hormones, IGF-1, prolactin, melatonin
* **Regional -** differential response to mediators --\> mane of lion can respond to androgen levels where females won't respond
* **Local -** extrafollicular, intrafollicular, stem cells, hormones, mediators, growth factors, cytokines (inflammatory mediators can affect hair growth)
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**Psoroptic mange (sheep scab)**
The image shows the typical yellow crusts of sheep scab. It is present in several sheep producing countries, including the UK. It causes severe itching in affected sheep if left untreated. Scaly lesions develop on the woolly parts of the body and sheep often bite themselves and rub against objects to relieve the irritation causing loss of wool. **Untreated sheep may lose weight**.
Please note: **Sheep scab is a notifiable disease only in Scotland**
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Example: **Lucilia sericata**, on the skin of a sheep – following a moist dermatitis such as fleece rot or dermatophilosis
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Alopecia
* Abscence of hair where it is normally present
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Hypotrichosis
* congenital alopecia
* or paucity of hair
* **may use this term if there isnt complete hair loss, but it doesnt matter much**
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4 principle mechanisms of hair loss
1. **Traumatic Removal of hair (self trauma) -** (most common cause across all species)
2. **Inflammatory** (damage to hair follicle) - demodecosis, Staph. folliculitis, dermatophytosis
3. **Malformed/dystrophic/dysblastic or atrophic** hair follicles unable to produce normal (or any) hair --\> follicular displacement - basically a clump of keratin
4. **Hair cycle arrest** (e.g. endocrinopathies)
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Symmetrical Alopecia in the Cat
* **self inflicted unless proven otherwise!**
* work up as pruritis
* Note: work up as inflammatory or not, BUT remember some lesions grossly looking non-inflammatory may reveal inflammatory histopathology
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Leishmania
**Inflammatory Hair loss in the Dog!**
* Leishmaniosis is a disease caused by **protozoan parasites** of the genus Leishmaniaand transmitted through the bites of female phlebotomine sand flies.
* Dogs are the main reservoir host for human visceral leishmaniosis caused by L infantum, and the disease is potentially fatal in dogs and people
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Some Inflammatory causes of hair loss
| (4 examples)
* dermatophytosis
* Leishmania (Secondary inflammation)
* Bacterial folliculitis
* Demodecosis
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Non-inflammatory causes of hair loss
* hair follicle/function problems
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Telogen effluvium
A **telogen effluvium** is when some stress causes hair roots to be pushed prematurely into the resting state. Telogen effluvium can be acute or chronic. If there is some "shock to the system", as many as 70% of the scalp hairs are then shed in large numbers about 2 months after the "shock".
## Footnote
**Premature/excessive exogen (shedding)**
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Hair Loss
(Impaired anagen promotion/premature catagen)
catagen - atrophy/recede of anagen bulb
* Hyperoestrogenism/hypothyroidism
* **Hair follicles can't start growth phase well or a re prematurely shut down**
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Hair loss
(impaired anagen induction/prolonged telogen)
* Hyperglucocorticism
* hyperoestrogenism
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Hair Loss
(if NOT self trauma...then inflammatory or non-inflammatory?)
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Scaling skin
More subtle
Often scaling --\> epidermis trying to repair fromm inflammation
Hyperpigmentation - where sun doesn’t show
Chronic inflammation likely
**Inflammation**
**Case of ringworm treated with glucocorticoids**
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- patches of hair loss
- very faint erythema in those patches (would see close up in practice)
**-demodecosis**
**INFLAMMATORY**
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Differentials in **Acquired Non-Traumatic Alopecia**
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* **telogenisation of the hair coat**
* Hormonal mediated coat abnormalities
* Hairs in the telogen phase do not get initiated into the anogen phase as they should - should be about 80% telogen, 20% anagen, but becomes about 100% telogen
* As hormonal influence persists - there is a synchronization of the hair coat into the telogen phase
* If you clipped the dog in that phase, it wouldn't really grow back well
* But remember you need to look at **SYSTEMIC SIGNS AS A SIGN**
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Acquired Non-Traumatic Alopecia
(non-inflammatory)
4
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Most common causes of an Alopecia work up:
## Footnote
**In order (4)**
* Inflammatory/parasitic causes are the most common and most easily fixable!
* **but always suspect traumatic removal of hair first! - if so, work up as pruritic skin disease**
* **consider inflammatory (infectious causes first), then endocrine, then lastly micellaneous alopecias**
* congenital reasons likely more apparent when young, but become more marked with age!
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Diagnostic Approach to hair loss
| (3 work ups)
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hypoallergenic dogs
| (not a real term though, disproven)
* essentially breeds thought to have a lack of shedding and therfore cause less allergies.
* BUT: **NOT TRUE**
* **these breeds have allergens we react to. shedding less allergens by hair, but likely salivary glands and anal sacs have allergens and the hair is a medium of transport**
* Tibetan Terrier. Tibetan terriers are proof that hypoallergenic doesn't mean no hair.
Maltese Terrier. ...
Shih Tzu. ...
Brussels Griffon. ...
Portugese Water Dog. ...
Soft-Coated Wheaten Terrier. ...
Poodle (Toy, Miniature, and Standard) ...
West Highland White Terrier.
