Sequential occurrence of recurrent Sweet syndrome and erythema nodosum without an underlying secondary cause: a case report

BACKGROUND: Sweet syndrome is a rare cause of acute fever and painful erythematous skin plaques. Erythema nodosum is acute or chronic tender erythematous skin nodules of bilateral shins. The concurrent presence of both dermatoses is rare but reported in the literature. There are no reported cases of recurrent and sequential Sweet syndrome and erythema nodosum without an underlying secondary cause. CASE PRESENTATION: We report the case of a 64-year-old Asian woman, who had possible Sweet syndrome 12 years ago and biopsy-proven erythema nodosum 5 years ago, presenting with an acute episode of Sweet syndrome. Extensive investigations did not reveal any underlying secondary cause. CONCLUSIONS: Recurrent Sweet syndrome and sequential presence with erythema nodosum raises suspicion if Sweet syndrome and erythema nodosum are different presentations of one disease, which warrants further study. This case proves that recurrent Sweet syndrome and erythema nodosum can occur in healthy individuals without an underlying malignancy or secondary cause.