ABSTRACT
Drugs and radiation can affect cell cycling and may lead to alopecia. This chapter reviews which drugs have been implicated in hair loss and explores the mechanisms of how pharmaceutical agents and radiotherapy can alter hair cycling and structure. The workup for any patient with hair loss must include a thorough drug history. One must understand the basic mechanisms of hair growth and cycling to understand drug-induced hair loss. Hair loss occurring a few days after drug intake indicates an effect on hair matrix cells. Hair loss developing weeks to months after drug intake may be due to hair matrix effects, but may result from changes in keratin production or changes in the hair cycle. Patients are sometimes more afraid of the hair loss and cosmetic disfiguration than of the underlying disease or therapy itself. Hair loss is a possible adverse effect of lithium carbonate, and may be noticed within weeks or years after commencing therapy.
