Abstract
Intradermal testing using extracts from Malassezia pachydermatis was conducted in 50 dogs with seborrheic dermatitis. Immediate reactions to M. pachydermatis antigen were observed in 17 (34.0%) of 50 dogs, and delayed reactions to it in 3 (9.4%) of 32 dogs. None of 10 control dogs showed any positive reaction to the antigen. Shampoo, either selenium disulfide or chlorhexidine, was effective in 19 (90.5%) of the 21 cases with negative reactions. In contrast, the same treatment was effective for only 3 (33.3%) of the 9 dogs with positive reactions. The remaining cases showed improvement with a systemic anti-yeast agent, ketconazole. This study indicates that M. pachydermatis may play a role as an allergen in some dogs with seborrheic dermatitis.
