Sarcoidosis is a chronic granulomatous disease of unknown etiology that basically affects lung and adenopathic tissue, although it can involve any tissue.1–9 Its diagnosis requires the combination of clinical, radiologic, and histologic findings and treatment varies according to its severity. Interferon has been implicated in the etiology of the formation of granulomas and in 1987 the first case of sarcoidosis secondary to the use of interferon alpha was reported.3 Approximately 100 cases of sarcoidosis related to the use of interferon have been published in the literature.4,5 Interferon is currently a widely used therapy for the treatment of hepatitis C. We present herein the case of a 48-year-old woman that presented with pain in both knees of one-month progression. Her past history included hepatopathy from the hepatitis C virus treated with triple therapy (telaprevir + interferon + ribavirin), which ended 2 months prior to symptom onset. Physical examination revealed 2 hardened, erythematous zones above the right knee with increased local temperature and no lesions in the pretibial zone (fig. 1). The analytic parametric studies were normal (ANAs, RF, ESR, and CRP, slightly elevated ACE) and the Mantoux test was negative. Chest x-ray revealed modest perihilar thickening. It was confirmed by tomography scan that also identified adenopathic perihilar and mediastinic conglomerates. Respiratory function tests were normal. Biopsy of the nodular lesions reported changes consistent with «subcutaneous sarcoidosis» (fig. 2). Follow-up and surveillance were decided upon. The patient had clinical improvement and symptoms disappeared 6 months later. All diagnoses of sarcoidosis within the last 2 years were reviewed in our hospital database and we found no other similar case.

Figure 1.

Hardened, erythematous zones above the right knee, with increased local temperature.

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Figure 2.

Non-caseating granulomas consistent «with sarcoidosis» are observed.

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There is a clear relation between the appearance of sarcoidosis and interferon alpha use and various cases of sarcoidosis activation/reactivation during the disease course of patients with hepatitis C virus undergoing said treatment.2,4,6,9

Symptoms can occur during treatment or up to 2 years after its suspension. Nevertheless, it is difficult to know the incidence of this entity.1

Even though the natural history of sarcoidosis is highly variable, in one study of patients with interferon-associated sarcoidosis, 85% of the patients were spontaneously cured and 10% of the cases became chronic, utilizing corticoids in the most severe cases.2 Other treatments that have been used are hydroxychloroquine10 and infliximab.11 The administration of corticoids can increase the viral burden and hepatitis C virus itself induces interferon alpha expression. 12

It is relatively common in medical consultations to find patients with hepatitis C virus, therefore if there are symptoms that lead to suspicion of sarcoidosis, the physician must take into account the association of this entity with interferon alpha use.