Plummer's nail

Plummer's nail is a clinical sign in which there is onycholysis, or separation of the nail from the nail bed, particularly affecting the ring and little fingers. It occurs in patients with thyrotoxicosis. About 5% of hyperthyroid patients display abnormal nail changes. Plummer's nail is also associated with psoriasis, traumatic injury, and allergic contact dermatitis.

The sign is named after Henry Stanley Plummer.