Congenital Skin Disorders Flashcards
List the etiological classification of skin diseases
- Congenital, hereditary skin diseases
- Ectoparasitic diseases (cat ear mites, sarcoptes)
- Bacterial (purulent dermatitis) (pyoderma?)
- Fungal diseases - Malassezia
- Allergodermatitis
- Immunmediated/autoimmune skin diseases
- Endocrinodermatopathies (cushings, hypoth)
- Keratinization defects
- Normergic dermatitis (chemical and physical causes)
- Neoplastic diseases
- Other (paraneoplastic) diseases
- Diseases affecting the skin and other organs
What is important to know regarding congenital, hereditary skin disorders?
🔺 histopathology is the base of the diagnosis;
🔺 to know:
- which breeds can be affected
- suggestion for the breeder for screening: is there any genetic test for that or no?
- what is the prognosis like?:
-> is the disease lethal or not?
-> is it „only” cosmetic?
🔺 grouped after the effected part of the skin structure
(hairshufts, epidermis, pigmentation, dermis, collagen, elastin, sebaceous gland, panniculus etc. - disorders)
Alopecia - name the types
- generalized alopecia
- hypotrichosis
- black follicle dysplasia
- colour mutant alopecia
- pattern alopecia
- menaoderma and alopecia of yorkshire
Generalized alopecia
Missing hair in certain areas
🔺Normal breeds selected for:
Abyssynian dog, African sand dog, Turkish naked dog, Peruvian hairless dog, Chinese crested dog
🔺Pathological cases reported:
m. poodle, c. spaniel, Belgian shepherd, whippet, beagle, bichon frise, basset, L. retriever
🔺Naturally occuring: sphinx cat
Describe the genetic background for generalized alopecia for the chinese crested dog
(A: hairless gene / a: hairy gene)
- AA lethal (1/4 puppies will die with 2 hairless parents!)
- Aa hairless
- aa „powder puff” (hairy)
Occurance of hypotrichosis, and what is it?
Siamese, Devon rex cat
- loss of hair (diffusly?) either at birth or just a few months old. This is due to a problem in the development of hair follicles or not having some or all of the follicles where hair will typically grow from.
Black hair follicle dysplasia: occurance, signs, diagnosis, treatment
• Occurrence: bearded collie, dachshund, papillon, basset
• Clin. signs: from 4 weeks hairs fall out, fail to grow, scaling
–> bicolour or tricolour coats lose hair only in the black areas at an early age. Large melanin granule deposits within the hair shafts and follicles are the hallmark of this disorder
• Diagnosis: skin biopsy (abnormal follicles, with keratine plugs)
• Treatment: antiseborrheoic shampoos (selenium disulphide, benzoyl peroxyde)
Color mutant alopecia - occurance, clinical signs and diagnosis
• Occurrence: in red and beige (fawn) dobermann, fawn Irish setter + blue individuals of some other breeds
–> aka blue Dobermann” syndrome, „blue dog” disease!
• Clin. signs: at 1- 3 years “moth eaten” alopecia on the black
parts of the coat + increased scale + papule formation
•Diagnosis: skin biopsy (cystic hair follicles filled with keratin)
Abnormal pigment (melanin) clumping in the hairshafts and subsequent changes in light refraction are responsible for the unusual coloration, and in severely affected animals, excessive pigment clumping causes breakage of the hairshafts and abnormal or stunted hairgrowth.
Pattern alopecia: occurance, signs, treatment, diagnosis
dachshunds • bilateral alopecia of the pinnae (males) • ventral alopecia (females) • no response to treatment • HP: miniturisation of hair follicles
Melanoderma and alopecia of Yorkshire
- onset at 6 month - 3 years (both sex)
- occurs on the nose and legs. symmetric alopecia and marked hyperpigmentation on the pinna, and in most cases also the bridge of the nose, tail and feet are affected. The alopecic and hyperpigmented skin has a smooth, shiny, and leathery
- spontaneous recovery is possible
List the possible congenital pigmentation degects
- hereditary vitiligo
- canine cyclic hematopoesis (grey colllie syndrome)
- tyronisinase deficiancy in chow-chow
hereditary vitiligo
- Occurrence: GS, Belgian shepherd, Rottweiler, Dobermann, Old English shepherd, dachshund
- Clin signs: Hypopigmentation on the nose, lip, buccal mucosa, facial skin, footpads, nails
Canine cyclic hematopoesis (Grey collie syndrome)
• Occurence: 6-12 weeks,
• Clin signs: pyrexia, lymphadenopathy, nonregenerative
anaemia, arthralgia, diarrhea
• Course: lethal after ish 3m (leukopenia ++ -> secundary infection -> death
(Treatment - bm transplant)
Tyrosinase deficiency in the chow-chow
- Cause: impaired melanin synthesis, transient
- occurs in puppies: pink tongue, hair shafts turn white
- sporadic? (Sp) recovery
Name the abnormalities of structural integrity
- Aplasia cutis (epitheliogenesis imperfecta)
- Cutaneous asthenia (Ehlers-Danlos syndrome,
rubber puppy disease, fibrodysplasia elastica) collagen
dysplasia - Dermatomyositis
- Canine ichtyosis (fish skin disease)
- Zinc-responsivedermatosis
- Schnauzer comedo syndrome
- (granulomatous)Sebaceous adenitis (SA)(!)
Aplasia cutis (epitheliogenesis imperfecta)apla
- occurs in both dogs and cats
- focal absence of epithelium where ulcers develop
- course: +/- fatal (milder cases may heal or be treated)
Cutaneous asthenia (Ehlers-Danlos syndrome,
rubber puppy disease, fibrodysplasia elastica) collagen
dysplasia
• Occurrence: beagle, dachshund, boxer, St. Bernard, GS,
Dobermann (at our clinic), Himalayan cat, DSH (domestic short hair) cat
• Clin signs: soft, velvet like skin, too flexible skin, tear of skin.
–> collagen binds the skin together - The skin is abnormally fragile. The skin flaps peel or slough off very easily, often without causing bleeding
- without bleeding, poor healing, multiple scars
+/- vasopathy, cardiac valve disorder, joint hyperflexibility (all organs where collagen play a role will be affected!)
• poor prognosis - euthinasia
Dermatomyositis
• Occurrence: rough collies, Shetland sheepdogs
• Clin signs: from 3 month, lesions: papules, vesicles, pustules, crusts on the nose, eyes, tips of pinnae and tail, bony prominences of the feet + muscle atrophy
—> skin+muscle inflammation! - smooth muscle –> megaesophagus may develope!
• Diagnosis: skin + muscle biopsy
Canine ichtyosis (fish skin disease)
- generalized hyperkeratosis on the skin and foot-pads (looks “scaly” crusty)
- mild improvement to antiseborrheoic and keratolytic ointments
- treatment: keratomodulating shampoo
- golden retriver ichtyosis - black scales seen in fur - gene test available!
Zinc-responsive dermatosis
- Hereditary zinc absorptions defect: malamut, huskies
- rare bc we have better food
- hyperkeratosis
- large breed dogs - during dev a large amount of calcium is needed -> temp zink deficiancy can develop
Schnauzer comedo syndrome
- Occurrence: exclusively male schnauzers
- Clin signs: comedones (skin coloured papules) along the dorsum, +/- papules, sec., folliculitis (black/discolored follicles)
- Treatment: benzoyl peroxyde
Sebaceous adenitis (SA)
Inflammation of the sebaceous glands - eventually leading to destruction of the glands. Many stages - last stage no glands left!
• should diagnose which stage - early stage still treatable!! (Follicular casts..) later alopecia inevitable, no follicles left..
• Occurrence(!!!red): Hungarian vizsla, akita, samoyed, poodle
• Clin signs: on the trunk: scaling, alopecia, seborrhea
• Treatment: antiseborrhoic drugs, cyclosporine, isotretinoin (vit A, PO)
(Granulomatous SA - inflamm, gran tissue…?)
List some miscellaneous conditions
- Acanthosis nigricans
- Primary idiopathic seborrheaa
Acanthosis nigricans
- Occurrence: exclusively dachshunds, 1-3 years
- Cause: multifactorial etiology? Unknown exactly rarely primary, usually secundary to eg. Bacterial+malazessia overgrowth?
- Clin signs: dry, dark patches of skin: typical localization, hyperpigmentation, lichenification
- Treatment: prednisolone (thinning+depigm), vitamin E, melatonin
- limited response to treatment
Primary idiopathic seborrhea
Common!
Seborrhea - always a secundary thing! (Something causing an inflammation eg yeast, this is how skin reacts?)
(excessive discharge of sebum from the sebaceous glands manifesting in itchy rash with flaky scales)
• occurs in cocker and springer spaniels
• rule out chronic dermatopathies
