Folliculitis - Symptoms and Causes

Authored by Dr Laurence Knott, 06 Jul 2017

Patient is a certified member of
The Information Standard

Reviewed by:
Dr Helen Huins, 06 Jul 2017

When hair follicles become infected, they swell into small pus-filled pimples. Each individual pimple looks like a small, rounded, yellow-red spot.

folliculitis

Folliculitis can occur anywhere on hair-bearing skin. (It could not, for example, occur on the palms of the hands where there is no hair.) There are a few specific types of folliculitis that deserve a mention:

  • Sycosis barbae - this is the medical name for a long-term (chronic) folliculitis in the beard area of the face in men (and some women). It often affects the upper lip and it can be difficult to treat. The skin is painful and crusted, with burning and itching on shaving. Numerous pustules develop in the hair follicles. Some men grow a beard to solve the problem.
  • Hot tub folliculitis - as the name suggests, this tends to affect people who use hot tubs a lot. The hot water encourages germs (bacteria) called Pseudomonas spp. to grow (particularly if there is not enough chlorine in the water to keep it clean). Bathing in this 'soup' of bacteria can increase your risk of folliculitis. This type of folliculitis is generally harmless and is prevented by proper maintenance of hot tubs. Showering after using the hot tub does not seem to reduce the chance of folliculitis.
  • Gram-negative folliculitis - this is a type of folliculitis that may occur after acne has been treated with long-term antibiotics. Different bacteria are involved (not staphylococci). Gram-negative refers to a type of stain that is used in a laboratory to identify different types of bacteria.

Pseudo-folliculitis is not really a true folliculitis. It does look similar, as little lumps form at the bases of hairs. These lumps do not contain pus. They are actually due to ingrowing hairs. Sometimes this problem causes scarring. Pseudo-folliculitis is more common in people with curly or Afro-Caribbean hair.

As mentioned above, these can cause a condition that looks like folliculitis. They are hairs that have curled around and grown back into the skin. Anyone can have ingrowing hairs (also called ingrown hairs), but they are more common in people who have very curly or coarse hair. Curly hair is more likely to bend back and re-enter the skin, especially after it's been shaved or cut. Ingrowing hairs may also be caused by dead skin cells blocking the hair growing as normal.

Ingrowing hairs often irritate the skin and make a raised, red bump (or group of bumps) that looks like a little pimple. Sometimes the bump(s) can be painful. In men, ingrowing hairs often pop up as a bunch of little bumps on the chin, cheeks, or neck after they've shaved. In women they often occur on the legs or bikini area.

Often an ingrowing hair will go away on its own. If it doesn't go away, an ingrowing hair can become infected, make the skin dark, or leave a scar. This is more likely if you've been scratching or picking the hair.

Most cases of folliculitis are due to an infection with a germ (bacterium) called Staphylococcus aureus (S. aureus). This bacterium is carried harmlessly in the noses of many people, without causing any problems. Occasionally, other germs (bacteria) are the cause of folliculitis.

Folliculitis usually occurs at sites where hair follicles are damaged by friction or shaving, or where there is blockage of the follicle. Excessive sweating (hyperhidrosis) due to overactivity of the sweat glands can be another cause. Sometimes, using a steroid cream on the face can trigger a bout of folliculitis. The most common site affected is the beard area of men although women with facial hair can get it in this area too. Other common sites for folliculitis are the arms, legs, armpits and buttocks.

Other conditions involving hair follicles can occur. Furuncles and carbuncles are the medical names for what you would call a boil. Both are skin infections caused by germs (bacteria) - usually S. aureus. A furuncle is a skin infection that involves the hair follicle and surrounding skin. Clusters of furuncles can join together under the surface of the skin, forming a carbuncle. A carbuncle means the infection has spread more deeply in the skin and scarring is more likely. Carbuncles and furuncles are generally much bigger and more painful than the tiny pustules you get in folliculitis. They may need to be cut into (incised) and drained (lanced) to let the pus out.

Sometimes acne can look similar to folliculitis too. The main difference is that in acne, the hair follicles become plugged with oils (from glands in the skin) and dead skin cells. There may also be an overgrowth of certain bacteria that can live in hair follicles.

Further reading and references

I am 63 and for the last 22 years have suffered with excessive sweating on my head and face, which seems to be getting worse.  This is uncomfortable and embarrassing.  If I do anything even slightly...

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