Intradermal test reactivity to Malassezia pachydermatis in healthy basset hounds and basset hounds with Malassezia dermatitis

Research on fungal skin infection affecting dogs

source: R. Bond et al
Veterinary Record vol 151 no 4, July 27 2002
starts p105, 5 pages long

Some breeds of dogs, like basset hounds, West Highland white terriers, and cocker spaniels are prone to skin lesions associated with a yeast infection, linked to Malasezzia pachydermatis, and characterized by greasy dermatitis with a large yeast population. Affected dogs often respond to antifungal therapy, which can stop the itching. There is some evidence that basset hounds suffering from this condition may also be affected by defective cell-mediated immunity.

In this study, basset hounds and beagles were used to assess how their skin responded to M pachydermatitis antigens, using both healthy basset hounds (eight dogs), and those affected by skin lesions (17 dogs), as well as healthy beagles (19 dogs). The aim was to assess differences in intradermal responses. Two affected basset hounds and one beagle showed reactions of the wheal and flare type 15 minutes after the antibodies had been injected. Almost all of the basset hounds had reactions 24 hours after injection, whether or not they had previously been affected, while few beagles showed this reaction. Both previously affected and previously healthy basset hounds showed similar gross lesions in response to the antigen extracts.

It is unclear why the reactions were delayed, and why both healthy and affected dogs showed such a reaction. It may be that these dogs were hypersensitive to M pachydermatitis allergens, or their immune response may tend to favour colonization by M pachydermatitis. More research is needed to clarify links between this sort of response to injections of M pachydermatitis-derived substances, and the effect on dogs of colonization and yeast infection on the skin.