Nail Sarcoidosis Presenting with Longitudinal Erythronychia.

A 37-year-old woman presented with progressive longitudinal erythronychia and onychorrhexis of the toenails. She had a history of sarcoidosis of the lung and nose, which was silent without treatment at the time of presentation. Histopathological examination of a nail matrix biopsy revealed granulomas with palisading histiocytes in the connective tissue and a lymphocytic infiltrate in and around the granulomas without necrosis. Based on the clinical presentation, medical history, and histopathological examination, the diagnosis of nail sarcoidosis was made. Treatment with triamcinolone acetonide 40 mg/mL resulted in the disappearance of the onychorrhexis and a significant improvement of erythronychia. To our knowledge, a clinical presentation with longitudinal erythronychia as seen in our patient has not been previously described. Bone involvement of the underlying distal phalanges and systemic involvement can be paucisymptomatic but are present in most patients with sarcoidosis of the nails. Nail and bone involvement are both regarded as features of chronic and systemic sarcoidosis. Screening for bone and systemic involvement should be performed in all patients with nail sarcoidosis, as this may influence decisions on treatment and follow-up. Therefore, it is important to recognize longitudinal erythronychia as a possible clinical sign of nail sarcoidosis.