Purpura, or bleeding under the skin, is one of the symptoms of acute radiation sickness. In the days to weeks following the atomic bombings, the heavily exposed survivors experienced fever, nausea, vomiting, lack of appetite, bloody diarrhea, epilation, and 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: 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.