[Cyclosporine-induced follicular eruption]

Cyclosporine is one of the immunosuppressant agents most widely used in the prevention and treatment of organ transplant rejection and also in autoimmune diseases. Many cutaneous side effects have been described with oral cyclosporine, mainly in transplant recipients, for example, hypertrichosis, gingival hyperplasia and viral skin infections. Here, we report an unusual follicular eruption induced by this drug.

A 22-year-old man presenting cystic fibrosis received a double-lung graft in January 2005. Six weeks later, he developed a subacute eruption of follicular papules, not highly pruritic, located mainly on the trunk, the extensor surfaces of the limbs and the face. Diagnosis of cyclosporine-induced follicular eruption was adopted on the basis of the histological and microbiological findings. Complete regression was obtained after switching to tacrolimus.

Three similar cases were previously reported characterized by typical follicular changes different from those observed in hypertrichosis or pilar keratosis. This rare cutaneous side effect may be explained by the direct action of cyclosporine on the pilosebaceous unit: this drug is known to extend the anagen phase of the follicular cycle and to induce toxic follicular dystrophy at higher tissue concentrations. This particular toxicity is usually seen after many months of treatment. In our patient, the time to onset was shorter, probably due to occasionally excessive plasma concentrations.