A second injection may be given 6 weeks later is no hair growth has occurred. No age, breed, or sex predilection has been identified. Begin as soft, painless swelling of multiple footpads on multiple paws. Footpads may feel mushy or be scaly. Footpads may ulcerate or become secondarily infected.
Lameness is uncommon unless feet are infected or ulcerated.
Some cats may have a concurrent plasma cell stomatitis or immune-mediated glomerulonephritis or amyloidosis . Cytology will reveal plasma cells, lymphocytes, and neutrophils. Histology is characterized by superficial and deep perivascular dermatitis with plasma cells predominating. Lesions may spontaneously regress, and treatment may not be needed. Response to therapy is generally seen within 2 to 3 weeks, but 10 to 14 weeks of therapy may be needed.