Nail damage can vary greatly and rarely has one single cause. Depending on whether it is associated with local or general disorders, the consequences are chiefly cosmetic, sometimes causing embarrassment or pain. Age, diabetes, suppression of the immune system and peripheral vascular disorders are contributory factors. Nail growth is slowed down by cold temperatures and by disruption of the blood supply.

Local causes of nail damage are chiefly infections, trauma, tumours and various skin diseases. Prolonged exposure to water and irritants or allergens can cause nail brittleness and loss, coloration anomalies. Nail damage is observed in many general medical conditions, including psoriasis and other skin diseases and chronic illness.

Several drugs expose patients to nail lesions through various mechanisms, particularly cytotoxic agents (anticancer drugs) and anti-infectives. Cytotoxic drugs often cause embarrassing and sometimes severe or painful nail lesions. Anti-infectives, including tetracyclines, fluoroquinolones, antimalarial and leprosy drugs expose patients to lesions associated with light, such as nail loosening and discoloration. Retinoids, used in the treatment of acne, expose patients to nail brittleness, inflammation and deformation.

The damage is generally reversible but sometimes persists for several years.

©Prescrire 1 July 2014

"Drug-induced nail disorders" Prescrire Int 2014; 23 (151): 180-182. (Pdf, subscribers only).