Ask the Veterinarian/skin mystery
I was wondering if you could clue me in to any disorders that might causer hyperkeratinization of the hair shaft, causing dysplastic clumps of hair. In appearance I can only like it to Vitamin A deficiency. The hairs clump to the skin and form an almost sap-like layer, with detachment of the hairs, allowing clumps to be easily pulled out. Although there is a strong, yeasty odor, the last fungul culture was negative and there is, of course a bacterial component. This has been ongoing for several years in a middle aged golden retriever. Laser therapy and medicated baths, along with appropriate antibiotic therapy have allowed hair regrowth, but the crusty lesions remain, generalized. The hair on all four limbs and the nose and face are uniformly unchanged, dislodge easily and pull out in clumps, with epithelial cells and this apparently sebaceous sap-like coating. Any ideas?
First, let me say that without an examination, I cannot make any type of diagnosis on the internet. I can recommend to you that you see a board certified veterinary dermatologist.
Has this dog been checked for low thyroid hormones? Has the skin been checked for bacterial infection, especially Methicillin Resistant Staph? Many of these sappy lesions are actually bacterial pustules that rupture. Some dogs will get these lesions from a condition called sebaceous adentis, although it is rarely found in a Golden. Has skin cytology been done for Malassezia yeasts (these do not grow on routine fungal cultures)? Since this is a Golden, I would also strongly urge you to have him tested for atopic dermatitis (allergies). If all of these things are negative, then a skin biopsy of the active lesions may give your vet some insight as to the nature of the skin disease (allergic, infected, parasitic, neoplastic, immune mediated, vascular problems, etc.)
In dermatology, a proper diagnosis is the hard part. Once we have a correct diagnosis, then treatment protocols for a partiucular disease are usually pretty effective.