Intradermal test reactivity toMalassezia pachydermatisin healthy basset hounds and basset hounds withMalasseziadermatitis

Nineteen healthy beagles, eight healthy basset hounds and 17 basset hounds withMalasseziadermatitis were tested intradermally with two extracts ofM pachydermatis. One healthy beagle and two affected basset hounds showed wheal and flare reactions 15 minutes after the injection. Delayed reactions, consisting of erythematous macules and plaques, were commonly observed 24 hours after the injection in both the healthy and affected basset hounds, but occurred infrequently in the beagles. At 24 hours the diameters of the lesions in the healthy and affected basset hounds were significantly (P<0.01) greater than those in the healthy beagles, but the diameters in the healthy and affected basset hounds did not vary significantly. Delayed reactions in six of the basset hounds withMalasseziadermatitis were characterised histologically by superficial perivascular and periadnexal infiltrates of neutrophils and lymphocytes.