What is Folliculitis?
Folliculitis is the inflammation of the hair follicles on the skin caused by a bacterial, fungal or viral infection. The bacterial agent often responsible for folliculitis is Staphylococcusaureus. The infection can be shallow or deep depending on the extent of disease.
It can affect people at any age, though it is more common during adolescence. In fact, acne, which usually develops during teenage years, is a type of folliculitis.
It can be characterized by pus-filled bumps surrounding the hair follicle, which becomes small red spots when the pus is already drained. It also produces a “chicken skin” appearance on the affected area. A furuncle or a boil may also develop when the inflammationreaches the sebaceous gland. It may develop in any hair-bearing areas of the skin, but it usually affects the chest, back, buttocks and lower limbs. 
Picture 1: An infected hair follicle in folliculitis
Image source: healthandfitnesstalk.com
Picture 2: Pus-filled blisters in folliculitis
Picture 3: Red spots all over the abdomen in folliculitis
Image source: upload.wikimedia.org
Causes of Folliculitis
Folliculitis can be caused by different microorganisms. The most common infectious agentis the bacteria Staphylococcusaureus, which is normally found on the skin. Other infection-causing agents include other types of bacteria and some types of viruses and fungi. 
Folliculitis develops when the skin is irritated, which can be caused by the following: [2,3]
- Insect bites
- Friction caused by tight clothing
- Obstruction of follicle caused by some cosmetic products or any oil- or wax-containing substances
- Improper shaving
- Chemicals, such as coal tar
- Topical steroids
Folliculitis can also likely develop in cuts or surgical wounds. People with diabetes or HIV are also more prone to developing folliculitis.
Poorly cleaned bath tubs can also cause a certain type of folliculitis, which is known as hot tub folliculitis. 
Symptoms of Folliculitis
The symptoms of folliculitis can vary depending on the infecting agent, but the most common symptoms are the following: 
- Clusters of tiny red spots develop around the hair follicle
- Pus-filled lesions that tend to crust after some time
- Erythema or redness on the affected area
- Itchy and sensitive skin
Types of Folliculitis
Folliculitis is classified into two types: superficial and deep. Superficial folliculitis affects only the upper portion of the hair follicle, while deep folliculitis involves the whole hair follicle and can affect deeper parts of the skin.
1. Staphylococcal folliculitis
This is caused by Staphylococcusaureus, and is the most common type of folliculitis.S. aureus is a bacterial agent that normally resides on the skin and has easy access to infect cuts or open wounds. It is characterized by white, itchy, pus-containing bumps that can occur anywhere in the body. 
Picture 4: Staphylococcus folliculitis
2. Pseudomonas folliculitis (Hot tub folliculitis)
This is caused by Pseudomonas aeruginosa, which can proliferate in hot tubs with imbalanced chlorine and pH levels. This happens when the hot tubs are not properly maintained. Red rashes may manifest within 8 hours to 5 days of exposure to P. aeruginosa. The rashes usually appear in areas where the water can accumulate, such as in the edges of swimsuits.
Picture 5: Hot tub folliculitis (Pseudomonas Folliculitis)
Image source: dermnetnz.org
3. Barber’s Itch
This is caused by the fungus Tinea barbae and results in white boils, which are extremely irritating.
Picture 6: Tinea barbae – (Barber’s Itch)
It is similar to barber’s itch, but is caused by extremely small cut or shaved hair curling back to the skin, causing irritation. Dark or keloid scars may develop in some cases. This occurs more often in black men or in people with curly hair. 
Picture 7: Pseudofolliculitis barbae
Image source: crutchfielddermatology.com
5. Malassezia folliculitis
Formerly known as Pityrospyrum folliculitis, malassezia folliculitis is causedby a yeast infection known as malassezia. It appears as small pink pustules or papules. This is predominant in teenagers or adolescents but also affects a great number of adults, specifically men. The infection mostly affects the chest, arms, neck, shoulders and face. 
Picture 8: Malassezia folliculitis
Image source: advancedskinwisdom.com
6. Herpetic folliculitis
This is caused by HSV-1 or the Herpes Simplex Virus-1 resulting in cold sores around the mouth area, usually in the upper lip portion. Folliculitis develops when the cold sore is accidentally scraped when shaving. 
Picture 9: Herpetic folliculitis
Image source: fujita-hu.ac.jp
7. Scalp folliculitis
It is an inflammatory disorder of the hair follicles of the scalp. This medical condition is also known as ‘Proprionibacterium’ folliculitis or ‘acne necroticamiliaris’. It manifests as small, itchy pustules on the scalp.
Picture 10: Scalp folliculitis
Image source: dermnetnz.org
This type of folliculitis develops in the beard area of men when they start shaving. Initially, it affects the skin on the upper lip, chin and jaw, and spreads as shaving continues. Severe forms can cause scarring around the mouth area.
Picture 11: Sycosisbarbae
Image source: domekaformadero.files.wordpress.com
2. Gram-negative folliculitis
This occurs on people who are on an antibiotic treatment in a long-term basis. Due to the antibiotics, the normal level of bacteria is altered or disturbed, leading to an overwhelming population of gram-negative bacteria. This can aggravate the pre-existing lesions and can be temporarily treated by stopping the consumption of antibiotics as per the doctor’s advice.
Picture 12: Gram-negative folliculitis
Image source: dermnetnz.org
3. Boils and carbuncles
When the attack of staphylococcus bacteria is severe, it results in pus-filled boils which are very painful. The larger the boil, the greater is the chance of scarring.
When there is a large number of boils formed into a cluster, then it is called a carbuncle. This is severe and healing usually takes longer period. The common areas affected are the nape, shoulder blades, back and thighs.
Picture 13: Carbuncle
Image source: beltina.org
4. Eosinophilic folliculitis
The condition is also identified as eosinophilicpustular folliculitis. Patches of pus-filled lesions are seen on the upper body, specifically the upper arms or the back of people suffering from HIV/AIDS. Yeast-like fungus is responsible for this and can lead to hyperpigmentation upon healing.
Picture 14: Eosinophilic folliculitis
Image source: dermnetnz.org
5. Genital folliculitis
It is caused byStaphylococcus aureus and occurs mainly in the groin or the genital area. The lesions formed may be filled with pus. This is usually difficult to cure due to its location.
6. Folliculitis decalvans or tufted folliculitis
The condition is identified as inflammatory alopecia as this can be seen primarily on the scalp. It can result to serious scarring and permanent hair loss on the affected area because of the destruction of the hair follicle. Folliculitis decalvans usually develops when several hairs are tufted on the same hair follicle.
Picture 15: Folliculitis decalvans or tufted folliculitis
Image Source: dermnetz.org
Diagnosis and Treatment of Folliculitis
Generally, the medic or the dermatologist will examine the skin physically.
A sample of the pus is also cultured and tested in the laboratory to determine the infecting agent. Hair samples are also microscopically examined in potassium hydroxide to identify fungal infections.
A biopsy testing is sometimes required, especially when eosinophilic folliculitis is suspected.
Treatment of folliculitis depends on the severity of the infection. Mild cases sometimes require no treatment as these heal on its own in about 2 weeks. Some treatment can be applied at home to accelerate the disappearance of the symptoms, such as:
- Warm compress containing Burrow’s solution (aluminum acetate solution) or vinegarhelps to drain the pus.
- Medicated shampoos, soaps, lotions and moisturizers can help.
- Antibacterial wash that contains benzoyl peroxide or clorhexidinemay be used.
- Do-it-yourself treatment, such as oatmeal lotions and scrubs, are believed to be effective too. [1, 10, 11]
Antibiotics are also prescribed by the dermatologist in moderate to severe cases of folliculitis. For bacterial folliculitis, the following antibiotics are commonly used :
- Clindamycin (topical)
- Metronidazole (topical)
- Cephalexin (oral)
- Dicloxacillin (oral)
- Doxycycline (oral)
- Minocycline (oral)
- Tetracycline (oral)
- Ciprofloxacin (oral)
- Levofloxacin (oral)
Fungal and yeast infections can be treated with the following :
- Ketoconazole (topical)
- Miconazole (topical)
- Terbinafine (topical)
- Fluconazole (oral)
Discolored skin or hyperpigmentation can be managed using the following :
- Kojic acid
- Hydroquinone, 2-4%
- Azelaic acid, 15-20%
Although it is usually easy to treat folliculitis, it is still best to prevent the development of the infection. Here are some preventive measures to be observed to prevent infection: 
- Observe proper hygiene. Bathe daily with antibacterial soap and shampoo, especially after exposure to chemicals.
- Avoid sharing personal items, such as towels and other clothing items. Use clean towels and garments after bath.
- Avoid scratching or scraping the bumps.
- Do not shave around the bump area.
- Use a clean razor blade during shaving.
- Depilatory creams or lotions can be used to avoid shaving.
- Avoid wearing tight clothing to reduce friction on the skin.
- Avoid applying oils or oil-containing products on the skin, as these can clog the pores of the skin, causing folliculitis.
- Make sure to shower with antibacterial soap after using public tubs or pools.
- Maintain the cleanliness of personal bath tubs.
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