Epilation, or loss of hair, is one of the symptoms of acute radiation sickness.

Hair is made of protein which is formed by a cluster of cells residing in the hair follicle or hair bulb (see Hypothetical mechanism of epilation). These cells die when exposed to radiation or toxic chemicals (eg, chemotherapeutic agents for cancer). As a consequence, each hair becomes thinner and, when combed, easily is broken, which is recognized as hair loss, ie, epilation.

In the days to weeks following the atomic bombings, the heavily exposed survivors experienced fever, nausea, vomiting, lack of appetite, bloody diarrhea, epilation, purpura or petechia, sores in their throat or mouth (nasopharyngeal ulcers), and decay and ulceration of the gums about the teeth (necrotic gingivitis). The time of onset of these symptoms varied, but it generally occurred sooner among the heavily exposed.

Editor’s note: Definition adapted from The Effects of Atomic Radiation. A Half-Century of Studies from Hiroshima and Nagasaki, by William J Schull, p 12, Wiley-Liss, New York, NY, 1995.