Cyclosporine‐induced psoriasiform‐lichenoid dermatosis in four dogs: Successful treatment with antibiotics and cyclosporine dosage reduction

Four dogs received cyclosporine at dosages of 8.6–17.5 mg/kg/day for 7–10 months to treat immune‐mediated diseases. These dogs developed multiple, well‐circumscribed lichenoid plaques with erythema and hyperpigmentation; additionally, thick scales appeared around the eyes, mouth and inside the auricles, and spread to almost the entire body. On the basis of histopathological examination and medication history, the four dogs were diagnosed with cyclosporin‐induced psoriasiform‐lichenoid dermatosis. Three of the four dogs exhibited marked improvement or disappearance of the skin lesions after systemic administration of antibiotics and reduction of the cyclosporine dosage; in the other dog, the lesions disappeared after systemic administration of antibiotics. Cyclosporine‐induced psoriasiform‐lichenoid dermatosis is believed to be multifactorial, involving the immune system and resident cocci on the skin.