Folliculitis is inflammation of a hair follicle caused by infection, chemical irritation or physical injury.

Folliculitis usually appears as small, white-headed pimples. It can occur in any part of the skin, but is especially common on the face, scalp, thighs, legs and groin area. Some types of folliculitis only infect the upper portion of the hair follicle, whereas others can infect deeper portions of the follicle.

Folliculitis begins when the hair follicle is damaged by friction from shaving or from wearing tight clothing. The follicles are more susceptible to infection when they are damaged. Folliculitis is more common in people who are obese and people who have a suppressed immune system due to diabetes, acquired immune deficiency syndrome (AIDS) or other medical conditions.

Some types of folliculitis occur when common bacteria have access to damaged hair follicles. Hot tub folliculitis occurs when Pseudomonas bacteria grow in poorly chlorinated hot tubs and are passed to the skin. Barber’s itch is caused when common Staphylococcal bacteria enter the skin after shaving.

Folliculitis is usually diagnosed by visual detection during a physical examination. In cases where folliculitis is not easily identified, a sample from a pustule (small, pus-filled blister) may be taken and sent to a laboratory, where it will be examined under a microscope to determine whether bacteria or fungi are present.

The signs and symptoms of folliculitis vary according to the type of infection, but superficial cases may look like a rash with small pimples similar to acne. With more severe types of folliculitis, large, painful and pus-filled pimples may develop.

Some types of folliculitis will disappear without treatment. Others can be treated at home with methods such as warm compresses and over-the-counter antibacterial ointments. Physicians may also recommend treatment with medications such as antibiotics, antifungals or corticosteroids.

Some types of folliculitis cannot be prevented, but others may be prevented by taking the following precautions: not wearing tight clothing, shaving carefully and maintaining hot tubs properly.