02 - scaling and crusting disorders

Question 1

(infectious disorders)

(bacterial causes)

(dermatophilosis)

1. common in horses, source is other animals but not ery contagious
2. aka what?
3. bacteria?

Answer 1

2. rain rot
3. dermatophilus congolensis

Question 2

(infectious disorders)

(bacterial causes)

(dermatophilosis)

1. for an infection to develop must have what two conditions?
2. Cx?
3. dx?
4. tx?

Answer 2

1. moisutre, skin microtrauma
2. thick crusts with matted hair, eroded underneath
3. cyto of crust (branching organism), may need culture
4. systemic abx, topical shampoo

Question 3

(infectious disorders)

(bacterial causes)

(bacterial folliculitis and furunculosis)

1. what two bacteria cause?
2. 2° to what?

Answer 3

1. stap aures and psuedointermedius
2. skin microtrauma

Question 4

(infectious disorders)

(bacterial causes)

(bacterial folliculitis and furunculosis)

(types)

1. truncal (saddle rash) = ?
2. pastern =
3. tail pyoderma - lesions may develop secondary to what?

Answer 4

1. papules/nodules in saddle area
2. restricted to pasterns and fetlocks
3. tail rubbing

Question 5

(infectious disorders)

(bacterial causes)

(bacterial folliculitis and furunculosis)

1. dx?
2. tx?

Answer 5

1. cyto, may beed culture and sens for deeper
2. shampoo, oral abx

Question 6

(fungal causes - dermatophytosis)

1. fungal organisms invade what kind of structures?
2. this can be self-limiting, depending on what?
3. rarely zoonotic
4. tranmission?

Answer 6

1. keratinized structures
2. immune status of host
3. direct contact, fomite, environment

Question 7

(fungal causes - dermatophytosis)

Question 8

(fungal causes - dermatophytosis)

(tx)

1. most resolve spontaneously unless what?
2. avoid what?
3. whole body treatments req (lime sulfur, miconazole/ketoconazole)

systemic tx very expensive

4. environmental decontamination also important

Answer 8

1. immunocompromised
2. corticosteroids

Question 9

(parasitic causes)

(demodicosis)

1. can present as a scaling and alopecic disease; however, the nodular form is much more common

Question 10

(parasitic causes)

(cutaneous onchocerciasis)

1. onchocerca cervicalis microfilaria transmitted between horses via what?
2. presence of microfilaria in skin doesn’t cause Cx unless what occurs?

Answer 10

1. culicoides exposure
2. hypersensitivity

Question 11

(parasitic causes)

(cutaneous onchocerciasis)

1. 4 Cx?
2. dx = histo, response to tx
3. tx?

Answer 11

1. inflammatory facial lesions, ventral dermatitis, depigmentation, scarring alopecia
2. ivermectin

Question 12

(allergic and immunologic causes)

(irritant contact dermatitis)

1. how different from contact allergy?
2. typically multiple animals affected
3. much more common than contacy allergy
4. examples of irritating substances = insect repellents, parasiticides, detergents

Answer 12

1. irritating substance rather than immunologic rxn

Question 13

(allergic and immunologic causes)

(irritant contact dermatitis)

1. Cx = ?
2. tx = avoid substance, bathing

Answer 13

1. thinly haired areas, may be painful rather than pruritic

Question 14

(allergic and immunologic causes)

(contact dermatitis)

1. rare cause of skin disease
2. usually only one animal affected
3. usually in thinly haired areas (hair provides excellent protection)
4. what kind of hypersensitiivty?
5. tx?

Answer 14

4. type 4
5. avoid allergen, topical corticosteroids if required

Question 15

(allergic and immunologic causes)

(pemphigus foliaceus)

1. what happens with this?
2. cahracterized by what (lesions)?
3. common parts of body affected?

Answer 15

1. autoimmunity - loss of tolerance for self
2. subcorneal to intraepidermal pustules (superficial layers of the epidermis) -> resulting in crusts covering erosions or ulcers
3. face, head, coronary band

Question 16

(allergic and immunologic causes)

(pemphigus foliaceus)

1. dx?
2. tx?

Answer 16

1. skin bx for histopath
2. corticosteroids (immunosuppressive dose)

Question 17

(environmental causes: actinic dermatitis)

1. lesions induced by solar damage = sunburn
2. UV absorbing substances

phototoxic = ?

photoallergic = ?

Answer 17

2. ingestion of photoactive substances

require previous exposure

Question 18