1. Unpleasant sensation that provokes desire to scratch.
2. Most common symptom in dermatology
3. Epicritic (sharp, specific) vs Protopathic (generalized) itch
4. Frustrations often makes this a multiple veterinarian disease!
Must make accurate diagnosis for effective treatment
History and owner assessment is very important
1. Flea Allergy - Used to be most common, is it still?
2. Atopy – Second most common?
3. Adverse Reaction to Foods
4. Contact Allergy – rare, does it occur in cats?
Adverse reaction to food maybe a better name
Not all food reactors are immunologic
Not all immunologic food reactors are IgE mediated
Clinical signs similar to atopics
Test diet length from 4-10 weeks
Hills Z/D, D/D novel protein, Purina H/A
Royal Canin diets
20% of food reactors may only exhibit otitis externa
80% of food reactors have otitis externa
Serologic tests are worthless
EARS AND REARS?
Intense pruritus in the dog
Lateral elbows, hocks, ventral thorax and ear margins are most common affected areas
Usually! poor response to GCC therapy, may actually cause mites to increase
Contagious to other pets and humans (especially if dog sleeps in bed with owner)
Skin scrapings of nonexcoriated papules usually best areas to find mites (ear margins and ventral thorax)
Always treat if suspect
Ivermectin, Selamectin (Revolution), Moxidectin (Advantage Multi),
Lime Sulfur dips
Staphylococcus - Staph allergy/hypersensitivity is rare, often thought must show vasculitis on dermatopathology
Malassezia – Allergy to antigens or fermatation products. Desensitization Candidia
Dermatophytosis – Rare, usually T. mentagrophytes
CTCL – Variable from none to extreme
Mast Cell Tumor
Calcinosis cutis – can often be very pruritic. Especially a problem if Iatrogenic.
Sertoli Cell Tumor – Rare, but some cases of hyperestrogenism are pruritic
Drug Eruption (variable pruritus)
TEN – Most severe form, often fatal