What causes ingrown hairs?

Ingrown hairs occur when hair grows into the skin, which leads to inflammation, irritation and, in some cases, infection, according to Mayo Clinic. Ingrown hairs are sometimes caused by blocked hair follicles, which prevent the hair from growing regularly, says WebMD. Shaving and tweezing can also cause ingrown hairs.

More common in people who have coarse or curly hair, ingrown hairs often occur after hair is shaved or cut because it has a sharper edge and is better able to penetrate the skin, advises WebMD. Although ingrown hairs usually go away on their own, Mayo Clinic recommends seeking medical attention for chronic ingrown hairs.