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Why is unwanted desquamation so detrimental?
it represents a breach in the epidermal barrier, allowing unwanted pathogens into the body
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What is the purpose of the lipid layer? (5)
regulates permeability of the epidermis, regulates desquamation, exclude toxins, absorb chemicals, antimicrobial peptides
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What is the purpose of the corneocyte? (3)
mechanical reinforcement, provides hydration, UV protection
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When is desquamation normal?
in production of a fresh, intact barrier in the face of accumulated damage or changing body mass
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Dry, white/ gray scales; dull coat.
seborrhea sicca
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Greasy of oily, malodorous coat/skin.
seborrhea oleosa
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Associated with folliculitis (usually bacterial in origin); combination of dry and greasy scales.
seborrheic dermatitis
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What is the least common type of seborrhea?
primary- direct result of a disease process
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Types of primary seborrhea.
linear keratosis, epidermal nevus (hamartoma),coronary band dystrophy, cannon keratosis, mane/tale seborrhea
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Describe this disease.
- Coronary Band Dystrophy
- Idiopathic defect of cornification
- Draft breeds, mature horses, insidious onset
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Describe this disease.
- Cannon Keratosis
- Disorder of cornification- hyperkeratosis
- Localized to dorsal cannon
- Vaseline, treat secondary infection if present
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Describe this disease.
- Linear Keratosis
- Quarter horses, Belgians- Inherited
- Linear, vertical, unilateral band of hyperkeratosis
- Cosmetic blemish- don't treat
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Describe this disease.
- Epidermal Nevus (Harmatoma)
- Most commonly affects plantar metatarsus (can affect all 4 limbs)
- Dx by clinical appearance
- +/- secondary infections
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Describe this disease.
- Mane and Tail Seborrhea- Primary
- Seborrhea oleosa
- Pruritic
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What types of seborrhea can be treated vs cannot?
Primary can be managed, not treated; secondary can be resolved if underlying cause is determined and addressed
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Describe this disease.
- Secondary Nutritional seborrhea
- Alopecia- patchy
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Describe this disease.
- Immune-mediated Pemphigus foliaceus
- Foals
- Superficial pustural crusting disease
- Usually resolves without lifelong txt
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Describe this disease.
- Onchocerciasis
- Infectious- result from nematode infection
- Microfilaria migrate to skin, die, cause mazotti reaction
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What questions do you ask when taking a history to determine the cause of secondary seborrhea? (5)
duration, initial lesions and how have they progressed?, pruritus?, used any topical products?, other affected horses?
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What does pruritus present before seborrhea suggest?
allergic disease, parasitic disease
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What does pruritus after seborrhea suggest?
secondary bacterial folliculitis, yeast dermatitis
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At the minimum, you must perform a(n) _____________ to identify the cause of secondary seborrhea in order to...
superficial skin scrape; rule out ectoparasites.
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What is the purpose of performing surface cytology?
rule out bacterial infection and/or yeast infection
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How do you identify fungal infections?
DTM culture (dermatophyte test medium)
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Biopsy is used to... (2)
determine bacterial culture results, histopathology
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What are the 3 main considerations for treatment of seborrhea?
is it primary or secondary?, is there proper husbandry for the horse?, topical therapy is foundation of management/treatment
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Principals for normalizing keratogenesis. (3)
shampoo with cleansing an therapeutic properties, remove excess corneocytes, more severe dermatitis--> more potent shampoo
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Agents that remove excess corneal layers by solubilization of the intercellular cement; used in mild disease.
keratolytic agents
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Agents that function in the restoration of normal keratinocyte multiplication and the process of keratinization and epithelialization; indicated with more severe epidermal hyperplasia.
Keratoplastic agents
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What are indications for use of salicylic acid?
moderate to severe dry scale
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What are indications for use of sulfur?
moderate to severe dry scale with suspected secondary bacterial, fungal, or parasitic components
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What are indications for using a combination of salicylic acid and sulfur?
focal, adherent, thick, plaque-like greasy scale
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What are indications for use of benzoyl peroxide?
severe greasy seborrhea oleosa
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What are indications for use of tar (coal)?
severe seborrhea oleosa with epidermal hyperplasia
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When is it necessary to restore the barrier?
moderate to severe seborrhea sicca
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How do you restore flexibility of the stratum corneum (prevent cracking)? (3)
water (too transient), emollients (fill spaces), humectants (incorporated in SC and attracts water)
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