Omeprazole-induced hypertrichosis in two children.

Omeprazole significantly increases duodenal prostaglandin E2 synthesis. Prostaglandins are involved in hair growth regulation: prostaglandin E2 and prostaglandin F2 alpha stimulate hair growth, and prostaglandin D2 has an inhibitory effect. The use of omeprazole can cause acquired generalized hypertrichosis by increasing prostaglandin E2 levels.