Background and aim: Recurrence of sarcoidosis following complete remission and after a prolonged time of inactivity is considered a very unusual clinical event. The aim of this study was to investigate the clinical characteristics of a series of patients diagnosed as having recurrent sarcoidosis.
Methods: Recurrent sarcoidosis was defined as reappearance of the disease following complete spontaneous clinical, radiographic and other markers of activity resolution or following resolution after corticosteroid treatment and maintained for at least during 3 years without therapy. The clinical records of patients diagnosed as having episodes of recurrent sarcoidosis during a period of 28 years at the university hospital of Bellvitge in Barcelona, Spain, were reviewed.
Results: Seventeen patients suffering from 24 recurrences were identified. All but one patient were women. The mean follow-up time was 143 +/- 80 months (range: 52 to 282 months). Two patients had 3 recurrences, 3 had 2 and 12 had 1. The disease-free interval without treatment between the time when the disease became inactive after the initial presentation until the first recurrence varied from 10 months to more than 17 years, and the time of inactive disease without therapy between recurrences fluctuated from 23 months to more than 12 years. All the cases but one at onset and 17 at recurrence presented as Löfgren syndrome. At the time of the last control, 14 patients showed complete remission of the disease, one of them under corticosteroid therapy, 2 still had activity because of a recent recurrence, and 1 developed into chronic sarcoidosis.
Conclusions: Acute sarcoidosis, and particularly Löfgren's syndrome, may recur many years after complete remission and, in general, still has a good outcome. In consequence, a long-term follow-up is recommended even in patients with inactive disease. This clinical observation strongly suggests that a re-exposure to or reinfection by an extrinsic antigen triggers the new flare-ups of the disease.