FELINE URTICARIA PIGMENTOSA IN 3 RELATED SPHINX CATS

A pruritic maculopapular eruption with clinical and histological featu res similar to urticaria pigmentosa of humans is reported in three rel ated Sphinx cats. All cats shared the same grandsire, had a juvenile o nset of disease, and demonstrated similar historical, clinical and his tological findings. Physical examination revealed widespread bilateral ly symmetrical, erythematous, partially coalescing, crusted macules an d papules on the trunk, limbs, neck and head. A few macules exhibited a dark brown pigmentation. Dermatographism could not be elicited in an y of the cats. Histological examination of papules revealed the presen ce of a perivascular to diffuse dermal and subcutaneous infiltrate of well-differentiated mast cells. In one cat where systemic involvement was pursued, evidence of internal disease was not found.