Nail abnormalities: clues to systemic disease.

The visual appearance of the fingernails and toenails may suggest an underlying systemic disease. Clubbing of the nails often suggests pulmonary disease or inflammatory bowel disease. Koilonychia, or "spoon-shaped" nails, may stimulate a work-up for hemochromatosis or anemia. In the absence of trauma or psoriasis, onycholysis should prompt a search for symptoms of hyperthyroidism. The finding of Beau's lines may indicate previous severe illness, trauma, or exposure to cold temperatures in patients with Raynaud's disease. In patients with Muehrcke's lines, albumin levels should be checked, and a work-up done if the level is low. Splinter hemorrhage in patients with heart murmur and unexplained fever can herald endocarditis. Patients with telangiectasia, koilonychia, or pitting of the nails may have connective tissue disorders.