[Drug induced alopecia].

Hairs are produced in hair follicles that have a cyclic activity. The cycles that normal hair follicles go through are the metabolically active anagen phase, the catagen transitional phase and the resting telogen phase. Loss of more than 120 hairs daily is called alopecia. Drugs typically cause a diffuse, reversible alopecia by influencing one of the cycles that hair follicles go through. Because hair loss can have many causes, a causal relationship between a suspected drug and hair loss may be hard to prove. The principal categories of drugs that may cause alopecia listed in the literature are cytostatics, anticoagulants, interferons, tretinoid derivatives and lithium carbonate. The Netherlands Pharmacovigilance Foundation LAREB has received reports of alopecia as side effect of antimalarials, beta-receptor blocking agents, sex hormones, ACE inhibitors, angiotensin II antagonists and anticoagulants.