Case presentation :
A 2-year-old child had a one year history of polyarthritis and recurrent rash that was not objectified during consultations. The diagnosis of juvenile idiopathic arthritis was made. The patient was treated with nonsteroidal anti-inflammatory drugs and methotrexate. He was hospitalized after 2 months because of severe arhralgia and functional impairment. On skin examination, he had flesh-colored, non-itchy, 4 mm papular lesions on the arms and forearms with micropapular lesions on the trunk giving a keratosis pilaris-like appearance (figure 1 ). The ophthalmologic examination showed anterior uveitis with Koeppe and Busacca nodules. The child did not have respiratory symptoms or lymphadenopathy. The chest x-ray and blood tests were without abnormalities. A skin biopsy showed non-necrotizing granulomatous inflammation of the dermis, confirming the diagnosis of sarcoidosis (figure 2 ). The patient was treated with systemic corticosteroids with improvement of clinical signs.
Sarcoidosis in children poses a diagnostic challenge, especially before the age of 5, given the absence of the classic signs of sarcoidosis.1 It is characterized at an early age by the triad: uveitis, arthritis and rash. The cutaneous manifestations are variable: discrete and confluent papules, eczematiform, ichthyosiform lesions, subcutaneous nodules, symmetrical maculopapular lesions or erythroderma.2 The rash is characterized by exacerbations and remissions. It often precedes other signs and can be discrete and go unnoticed.
Authorship: All authors had access to the data and a role in writing this manuscript.