[Sweet's syndrome complicating isotretinoin therapy in acne]

We report a case of juvenile acne aggravated in the form of Sweet's syndrome by isotretinoin treatment. The late onset of ulcerative-hemorrhagic rectocolitis in this patient raised doubts about a possible relationship between Sweet's syndrome, acne and inflammatory colitis.

A 19 year-old male patient with no disease history of note was treated for juvenile polymorphous acne resistant to standard topical acne treatment using isotretinoin (Roaccutane) at a dose of 0.5 mg/kg/d. After one week of treatment, the patient presented a fever of 38.5 degrees C, joint pain and congestive, erythematous-edematous, maculopapular plaques in ring-like layout subsequently becoming pustular and necrotic. These lesions occurred on the face, neck and pinna of the ear. Some nodules were also noted on the lower limbs. Biological tests and histology examination of a skin biopsy were evocative of Sweet's syndrome. The outcome was rapidly favorable following discontinuation of isotretinoin and institution of systemic corticosteroids (0.5 mg/kg/d). Two years later, ulcerative-hemorrhagic rectocolitis was diagnosed with episodes of bloody diarrhea.

Treatment of acne with isotretinoin can occasionally induce inflammatory episodes of acne. To date there have been no reported cases of isotretinoin-induced Sweet's syndrome. The subsequent onset of ulcerative-hemorrhagic rectocolitis provides an indication of the complexity of the pathogenic mechanisms involved.