I also recall from immunology class that flea allergies usually come in a pattern as well (variable, gut generally similar)...
Fles allergy dermatitis: copy - pasted from the 2006 WSAVA congress:
1. Pruritus (itchiness) predominantly localized to the caudal one-half of the dog.
2. Characteristic distribution pattern--partially bilaterally symmetric pattern, involve the dorsal lumbosacral (back) region, tail-base, perineum (butt region!), medial (inside), caudal (outside) thighs.
3. Crusted papules (pimples) in the umbilical fold--(especially in male dogs), an under-appreciated clinical marker for flea allergy dermatitis.
4. Lesions--crusted papules, secondary lesions associated with chronicity.
5. Fibropruritic nodules--highly characteristic clinical marker of flea allergy dermatitis in susceptible dogs.
“Your birth is a mistake you'll spend your whole life trying to correct.” Chuck Palahniuk
I love pus but I hate people.
I can say words like undifferentiated gonads now!