Small Animal Dermatology, 3rd edition

438 DISEASES/DISORDERS

Alpha-hydroxy acids (e.g., glycolic acid): enhances desmosomal breakdown only

within the stratum corneum, promoting desquamation without loss of barrier

function

Sodium hypochlorite; useful for secondary bacterial andMalasseziaovergrowth;

best when combined with ceramides or moisturizers.

 Moisturizers:
Excellent for restoring skin hydration and increasing effectiveness of subsequent

bathings

Humectants: enhance hydration of the stratum corneum by attracting water from

the dermis; high concentrations may be keratolytic

Propylene glycol spray (50–75% dilution with water) applied frequently

Emollients: coat the skin; smooth the roughened surfaces produced by excessive

scaling; usually combined with occlusive compounds to encourage hydration of

the epidermis.

 Ceramides, phytosphingosines, and fatty acids: topical “repair products” can mimic

the composition of epidermal lipids (free fatty acids, ceramides, cholesterol, phy-

tosphingosines, etc.); phytosphingosines are proceramides that play a key role in the

natural defense mechanisms of the skin; ceramides comprise 40–50% of epidermal

lipids and function in the cohesion of the stratum corneum, control local flora, and

balance hydration; ceramides also have an antiinflammatory effect by inhibiting pro-

tein kinase-C via anti-IL-1 activity and decreasing PGE 2 ; components of normal epi-

dermal intracellular matrix; antimicrobial; necessary to maintain stratum corneum

hydration; abnormal levels reported in multiple conditions; application helps restore

epidermal barrier function; these components are available as “spot-on” topicals,

moisturizers and shampoo ingredients.

Systemic Therapy

 Specific causes require specific treatments (e.g., L-thyroxine for hypothyroidism; zinc

supplements for zinc-responsive dermatosis).

 Systemic antibiotics: secondary bacterial folliculitis.

 Ketoconazole 5–10 mg/kg PO q24h:Malasseziadermatitis.

 Prednisolone 0.5 mg/kg PO q24h tapered and discontinued when possible): inflam-

matory or hypersensitivity causes.

 Vitamin A in therapeutic dosages: 600–1200 IU/kg PO q24h.

 Retinoid drugs: varied success for idiopathic or primary seborrhea; reports of individ-

ual response to retinoids in refractory cases: isotretinoin (1 mg/kg PO BID to q24h);

if response is seen, taper dosage (1 mg/kg q48h or 0.5 mg/kg q24h).

 Cyclosporine 5 mg/kg PO q24h until controlled, and then decreased to minimal

effective maintenance dosage: keratinization disorder associated with hypersensitiv-

ity, sebaceous adenitis, epidermal dysplasia, ichthyosis and/orMalasseziadermatitis;

cyclosporine has been shown to inhibit keratinocyte hyperproliferation in psoriatic

human patients; some of the beneficial properties may be due to antiinflammatory

effects of the drug.

 Essential fatty acid supplementation: may be helpful in replacing abnormal lipid levels

in the skin.