Dermatologic manifestations of relapsing polychondritis (RP) have been relatively poorly studied compared to other manifestations. In this study we describe dermatologic manifestations in a large series of patients with RP and the corresponding pathologic findings. In this retrospective, single-center review of 200 patients diagnosed with RP according to Michet's criteria, we analyzed separately those suffering from associated diseases with potential dermatologic involvement or chronic dermatitis. Skin or mucosal biopsies taken from 59 patients were examined without knowledge of the clinical data. Among the 200 patients with RP, 73 had chronic dermatitis or associated diseases with potential dermatologic involvement, especially hematologic disorders (n = 24) and connective tissue diseases (n = 22). Among the other 127 patients, 45 (35.4%) had dermatologic manifestations: aphthosis (n = 21; oral in 14 and complex in 7), nodules on the limbs (n = 19), purpura (n = 13), papules (n = 10), sterile pustules (n = 9), superficial phlebitis (n = 8), livedo reticularis (n = 7), ulcerations on the limbs (n = 6), and distal necrosis (n = 4). Dermatologic manifestations were the presenting feature of RP in 15 cases (12%), and appeared concomitantly (n = 23) or not (n = 22) with attacks of chondritis. Histologic findings included vasculitis (n = 19, leukocytoclastic in 17 and lymphocytic in 2), neutrophil infiltrates (n = 6), thrombosis of skin vessels (n = 4), septal panniculitis (n = 3), and minor changes (n = 2). Patients with and without dermatologic manifestations did not differ with regard to male/female ratio; age at RP onset; frequency of auricular, nasal, or tracheobronchial chondritis; or frequency of rheumatologic, ocular, audiovestibular, renal, arterial, or venous involvement. The frequency of dermatologic manifestations (91% versus 35.4%; p < 0.0001), sex ratio (18 male/4 female versus 44 male/83 female, p < 0.0001), and age at first chondritis (63.3 +/- 14 yr versus 41.4 +/- 17 yr; p < 0.0002) were significantly higher in the 22 patients with myelodysplastic syndrome than in the 127 patients without any associated disease. In conclusion, although dermatologic manifestations occur frequently in patients with RP, especially in association with myelodysplasia, they are nonspecific and sometimes resemble those observed in Behçet disease or inflammatory bowel diseases. Their presence in the elderly warrants repeated blood cell counts to detect a smouldering myelodysplasia.