What is folliculitis?

Folliculitis is a common condition that is often found on the face, arms, upper back and lower legs. There are many different types, but all are marked by inflammation (swelling), infection or irritation of the hair follicle (a space within the skin that holds the root of a hair and the oil glands). When these follicles become infected or irritated, redness, irritation, itching and bumps can develop.

What are the types of folliculitis?

The types of folliculitis include the following:

  • Staphylococcus aureus folliculitis: Infection of the hair follicle with Staphylococcus aureus bacteria is one of the most common causes of folliculitis. Small red or white pus-filled pimples can be seen on the skin. The affected area often resolves (gets better) within a few days and can be cared for at home. In severe cases, however, folliculitis should be treated by a medical professional.
  • Pseudomonas aeruginosa (“hot tub”) folliculitis: Pseudomonas aeruginosa is a bacteria that thrives in heated, moving water (hot tubs, whirlpools, water slides). It can infect the hair follicle and cause a rash that looks a great deal like the one caused by the staphylococcal species. Sometimes the rash is itchy. Hot tub folliculitis typically fades on its own within a few days, but some patients may need medical treatment.
  • Malassezia folliculitis: Malassezia are a family of yeast that can normally be found on the skin. Sometimes, when Malassezia gets into the hair follicles, it can cause an itchy condition that looks like an acne breakout, usually on the upper chest and back. This form of folliculitis is aggravated (made worse) by sweat. Using an antidandruff shampoo every day to wash the affected areas of skin is often helpful.
  • Pseudofolliculitis barbae: Also called “razor bumps,” Pseudofolliculitis barbae usually occurs in the beard area. After beard hairs are cut with a razor, sharply trimmed edges can turn back into the skin, causing irritation. Pseudofolliculitis barbae is more common in people with curly hair, particularly African-American men.
  • Sycosis barbae: Sycosis barbae is a severe, potentially scarring form of shaving-related folliculitis. The entire hair follicle is infected, resulting in large red pustules.
  • Gram-negative folliculitis: Gram-negative folliculitis can occur after prolonged antibiotic use to treat acne. Over time, resistant bacteria grow and multiply, resulting in worsening acne.
  • Boils (furuncles): Boils, or furuncles, occur when the hair follicle becomes deeply infected. The boil is often red, tender and painful. It will come to a head after several days and may leave a scar behind.
  • Carbuncles: A carbuncle forms when several boils appear in one spot. Carbuncles are usually larger and are the combination of multiple infected hair follicles.
  • Eosinophilic folliculitis: This condition is usually seen in patients who are immunosuppressed (the immune system is not fully functioning). There is also a form that is seen in babies. Eosinophilic folliculitis is not infectious. It is characterized by itchy pustules, most often on the shoulders, upper arms, neck and forehead.

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