Any insult that impairs mitosis of hair follicle keratinocytes can cause anagen effluvium. Disruption to cell division in the hair matrix makes the hair narrowed at its base and susceptible to breakage just above the zone of keratinisation. The necrotic matrix forms plugs consisting of melanin, keratin and inner root sheath which are extruded through the follicular opening. This process is known as trichomalacia. The main causes of anagen effluvium are an infection, a drug, a toxin, radiation or an autoimmune disease.
