What is Folliculitis (Hair Follicle Infection)?
Folliculitis is a usual skin condition where the hair follicle gets infected or inflamed, leading to a pustule (a small blister with pus) or a red bump on the skin that has hair. While this condition is not critical and usually resolves on its own, it can be problematic for people with weakened immune systems and may sometimes progress to more serious diseases.
What Causes Folliculitis (Hair Follicle Infection)?
Folliculitis, a condition often caused by bacterial infection of the hair follicles, can also be triggered by viruses and fungi, or even be non-infectious. The causes of folliculitis vary and include:
– Superficial bacterial folliculitis: This common type is primarily caused by the bacteria Staphylococcus aureus, including both methicillin-sensitive and methicillin-resistant forms.
– Gram-negative bacterial folliculitis: or “hot tub” folliculitis, is a result of the bacteria pseudomonas aeruginosa, typically from exposure to contaminated water like in swimming pools or hot tubs. Other bacteria such as Klebsiella and Enterobacter can cause this too, especially after prolonged use of oral antibiotics.
– Pityrosporum Folliculitis: This type is fungal, caused by the Malassezia species, and usually found in adolescents due to the increased activity of their oil glands. It often appears over the shoulders, back, and neck. This condition can be suspected if someone’s acne does not improve or even worsens after antibiotic treatment.
– Viral folliculitis: This type is most frequently caused by the herpes virus, but also, though exceptionally rare, by Molluscum contagiosum virus. Herpes-caused folliculitis looks similar to bacterial folliculitis, but usually forms groups or clusters of lesions.
– Demodex folliculitis: It’s a controversial type, as it’s caused by the mite Demodex folliculorum that naturally lives on our skin. It’s estimated that this mite is present in about 80 to 90% of all humans.
– Eosinophilic folliculitis: This type is mostly found in individuals with advanced HIV or those with low immunity levels. Though a non-HIV variant has been noted as a rare side effect in patients undergoing chemotherapy. Its exact cause is unknown but it could result from an immune-related inflammatory disease and possibly an associated infection. It typically presents as red, itchy bumpy skin, usually on the scalp, face, and neck.
Risk Factors and Frequency for Folliculitis (Hair Follicle Infection)
Folliculitis is a condition that we don’t quite know how often it happens. However, we do know that certain people are more likely to get it. This includes those with a history of diabetes, obesity, those taking antibiotics for a prolonged period, those with a weakened immune system, and those who shave often. While it doesn’t affect one gender more than the other, certain types of folliculitis may be more common in one gender. For example, Malassezia folliculitis is seen more commonly in men than in women.
- We aren’t sure how often folliculitis occurs.
- People at risk of developing folliculitis include those with a history of diabetes, obesity, long-term use of antibiotics, weakened immune systems, and frequent shavers.
- It affects both genders equally, but some types might be more common in one gender. For instance, Malassezia folliculitis usually affects men more than women.
Signs and Symptoms of Folliculitis (Hair Follicle Infection)
Usually, a thorough medical history and a detailed physical examination are enough to make a diagnosis. Key points to consider during the patient’s history include:
- Recent increase in itching due to skin irritation
- History of increased sweating
- Use of topical corticosteroids
- Recent and/or long term use of oral antibiotics
- Exposure to hot tubs and/or swimming pools
- History of HIV with a CD4 count less than 250 or weakened immune system (e.g.
a patient who had a recent transplant and is on drugs to suppress the immune system)
The physical examination should include a thorough check of areas on the body where hair grows. This includes both arms and legs, as well as the chest, back, face, and scalp. The examining doctor should look for small pus-filled bumps in these areas that are surrounded by red, inflamed skin.
Testing for Folliculitis (Hair Follicle Infection)
Folliculitis, an inflammation of the hair follicles, is usually diagnosed based on a thorough review of the patient’s medical history and a physical examination. Most of the time, you don’t need any special tests or imaging to confirm it.
However, if the doctor suspects that the folliculitis is caused by the Malassezia fungus, they may do a KOH (potassium hydroxide) preparation to look at it under a microscope. Using this method, the doctor can see the fungal spores and filaments. Though the KOH preparation can also identify Demodex folliculitis (a type caused by a mite), it is not done frequently in everyday practice.
In the case of eosinophilic folliculitis, which is a particular type of this condition, a skin biopsy will usually be necessary to confirm the diagnosis.
Treatment Options for Folliculitis (Hair Follicle Infection)
Staphylococcal folliculitis, a skin condition caused by bacteria, can often clear up on its own within a few days if it’s mild with few pustules. However, when the condition is more severe, topical antibiotics like mupirocin and clindamycin might be used. If these fail, or deeper folliculitis such as furunculosis and carbunculosis is present, oral antibiotics like cephalexin and dicloxacillin may be considered.
In contrast, Gram-negative folliculitis usually goes away on its own in about a week to ten days with good skincare. If this is a secondary result of long-term antibiotic use, certain oral antibiotics that target the pseudomonas bacterium can be used. This includes ampicillin, trimethoprim-sulfamethoxazole, and ciprofloxacin.
Pityrosporum folliculitis, on the other hand, is best treated with antifungal medication taken by mouth. Topical antifungal treatment is possible, but systemic therapy is preferred as it can eliminate the Malassezia fungus from deeper within the skin. Itraconazole and fluconazole are often used for this, though fluconazole is generally preferred due to its fewer side effects.
In cases where folliculitis is due to viruses like herpes simplex or molluscum contagiosum, treatments typically used for those viruses are employed. These may include oral acyclovir, valacyclovir, and famciclovir for herpes, and curettage, cryotherapy, or topical cantharidin (which isn’t available in the U.S.) for molluscum contagiosum.
For Demodex folliculitis, caused by skin mites, anti-parasitic treatments like topical permethrin or oral ivermectin and metronidazole are used. One study found that using oral ivermectin and metronidazole together may be more effective than using either drug alone. Topical permethrin cream is typically started first.
Eosinophilic folliculitis is usually seen in patients with HIV. Treatment often starts with antiretroviral therapy for the patient’s underlying HIV. While this can improve or even resolve the skin condition in many cases, some patients may have a flare of this condition during the first six months after starting antiretroviral therapy. For these cases, additional treatments like topical corticosteroids, antihistamines, phototherapy, or itraconazole or isotretinoin can be used for a few weeks to months.
What else can Folliculitis (Hair Follicle Infection) be?
- Common acne
- Rosacea with red bumps and pus-filled spots
- Folliculitis caused by medication
- A long-term skin condition causing abscesses and scarring
- A condition caused by tiny mites burrowing into your skin
- Hair bumps caused by shaving
- A skin condition with small, rough patches
- Acne at the back of the neck that leaves scars
What to expect with Folliculitis (Hair Follicle Infection)
This condition is typically mild and often resolves on its own, so the chances of making a full recovery are really good. By maintaining good hygiene and managing any existing health conditions, the chances of it coming back can be kept to a minimum.
Possible Complications When Diagnosed with Folliculitis (Hair Follicle Infection)
Possible developments include a serious skin condition like cellulitis (skin infection) or an abscess (a pocket of pus). There might also be side effects from medication, including allergic reactions to the drug or harmful interactions between multiple medications.
- A serious skin condition like cellulitis or an abscess
- Allergic reactions to medications
- Harmful interactions between different medications
Preventing Folliculitis (Hair Follicle Infection)
In most instances of folliculitis, which is an inflammation of the hair follicles, patience is the best treatment because it usually clears up on its own. For more severe cases, doctors might prescribe treatments such as antibiotics, antifungal medicine, or anti-parasitic drugs. It’s also important for patients to maintain cleanliness of the affected area and apply a warm compress to it for 15 minutes, several times a day.
Patients should refrain from scratching or shaving the affected areas. This could make the irritation worse and might spread the source of the problem.
