Definition
By Mayo Clinic staff
With common names like hot tub folliculitis and barber's itch, folliculitis may sound more like a bad joke than a skin disorder. But folliculitis, an infection of the hair follicles, is no laughing matter. Severe cases may cause permanent hair loss and scarring, and even mild folliculitis can be uncomfortable and embarrassing.
Folliculitis usually appears as small, white-headed pimples around one or more hair follicles — the tiny pockets from which each hair grows. Most infections are superficial, and they may itch, but on occasion they're painful. Superficial folliculitis often clears by itself in a few days, but deep or recurring folliculitis may need medical treatment.
Symptoms
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Superficial folliculitisSuperficial forms of folliculitis include:
- Staphylococcal folliculitis. This common type of folliculitis is marked by itchy, white, pus-filled bumps that can occur anywhere on your body. When it affects the beard area of men, it's called barber's itch. It occurs when hair follicles become infected with Staphylococcus aureus (staph) bacteria. Although staph bacteria live on your skin all the time, they generally cause problems only when they enter your body through a cut or other wound. This can occur through shaving or with an injury to the skin.
- Pseudomonas folliculitis (hot tub folliculitis). The pseudomonas bacteria that cause this form of folliculitis thrive in a wide range of environments, including hot tubs whose chlorine and pH levels aren't well regulated. Within eight hours to five days of exposure to the bacteria, a rash of red, round, itchy bumps will appear that later may develop into small pus-filled blisters (pustules). The rash is likely to be worse in areas where your swimsuit holds contaminated water against your skin. You're at increased risk of infection if you have diabetes, a history of skin infections, or open cuts or sores.
- Tinea barbae. Caused by a fungus rather than a bacterium, this type of folliculitis develops in the beard area in men, causing itchy, white bumps. The surrounding skin also may become reddened. A more serious, inflammatory form of the infection appears as pus-filled nodules that eventually form a crust and that may occur along with swollen lymph nodes and fever.
- Pseudofolliculitis barbae. An inflammation of the hair follicles in the beard area, pseudofolliculitis barbae affects men with curly beards. It develops when shaved hairs curve back into the skin, leading to inflammation and, in rare cases, to dark raised scars (keloid scars) on the face and neck.
- Pityrosporum folliculitis. Especially common in young and middle-aged adults, pityrosporum folliculitis produces chronic, red, itchy pustules on the back and chest and sometimes on the neck, shoulders, upper arms and face. It's caused by the yeast-like fungus.
- Herpetic folliculitis. Shaving through a cold sore — a small, fluid-filled blister caused by the herpes simplex virus — can sometimes spread the herpes infection to neighboring hair follicles.
Deep folliculitis
Types of deep folliculitis include:
- Gram-negative folliculitis. This sometimes develops in people receiving long-term antibiotic treatment for acne. Antibiotics alter the normal balance of bacteria in the nose, leading to an overgrowth of harmful organisms (gram-negative bacteria). In most people, this doesn't cause problems, and the flora in the nose returns to normal once antibiotics are stopped. In a few people, however, gram-negative bacteria spread to the cheeks, chin and jaw line, where they cause new, sometimes-severe acne lesions.
- Boils and carbuncles. These occur when hair follicles become deeply infected with staph bacteria. A boil usually appears suddenly as a painful pink or red bump about 1/2 inch in diameter. The surrounding skin also may be red and swollen. Within 24 hours, the bump fills with pus. It grows larger and more painful for five to seven days, sometimes reaching golf ball size before it develops a yellow-white tip that finally ruptures and drains. Boils generally clear completely in about two weeks. Small boils usually heal without scarring, but a large boil may leave a scar. A carbuncle is a cluster of boils that often occurs on the back of the neck, shoulders or thighs, especially in older men. Carbuncles cause a deeper and more severe infection than does a single boil. As a result, they develop and heal more slowly and are likely to leave scars.
- Eosinophilic folliculitis. Seen primarily in HIV-positive people, this type of folliculitis is characterized by recurring patches of inflamed, pus-filled sores, primarily on the face and sometimes on the back or upper arms. The sores usually spread, may itch intensely and often leave areas of darker than normal skin (hyperpigmentation) when they heal. The exact cause of eosinophilic folliculitis isn't known, although it may involve the same yeast-like fungus responsible for pityrosporum folliculitis.
