What is scalp folliculitis?
Scalp folliculitis is an inflammatory disorder of the hair follicles in the scalp. The condition is also known as "acne necrotica miliaris" or "Proprionibacterium folliculitis".
Scalp folliculitis is characterised by small, very itchy pustules on the scalp, often most troublesome on the frontal hairline. There may be only a small number of lesions or they may be very numerous. They are hard to leave alone because of the itch. They often become sore and crusted.
What is the cause of scalp folliculitis?
The cause of scalp folliculitis is not well understood. It is generally considered to be an inflammatory reaction to components of the hair follicle, particularly the micro-organisms. These include:
- Bacteria (especially Cutibacterium acnes, but in severe cases, also Staphylococcus aureus)
- Yeasts (Malassezia species)
- Mites (Demodex folliculorum)
What is the treatment for scalp folliculitis?
The scalp affected by folliculitis should be washed with a mild normal shampoo as often as desired. Antidandruff shampoos containing antifungal agents such as ketoconazole or ciclopirox are sometimes helpful. Conditioner can be used if desired.
The following medications may be helpful for scalp folliculitis:
- Topical antibiotics eg fusidic acid gel, clindamycin solution, erythromycin solution
- Mild topical steroid lotions or creams
- Oral antihistamines
- Oral antibiotics, particularly long-term tetracycline
- Oral isotretinoin – long-term low dose treatment may be required
Acne necrotica is a more severe form of scalp folliculitis also known as "acne varioliformis" or "acne frontalis". In this condition larger follicular spots (papules) become inflamed then develop blackened crusts, finally leaving permanent pox-like scars. Acne necrotica may affect the face, scalp or other areas.
Perifolliculitis capitis abscedens et suffodiens is also known as "dissecting cellulitis" or folliculitis, or "perifolliculitis capitis".
Perifolliculitis capitis abscedens et suffodiens is a rare and severe form of scalp folliculitis sometimes associated with acne conglobata, hidradenitis suppurativa and spinal arthritis (spondyloarthropathy). It most often affects black adult men but may rarely occur in white-skinned individuals, females, and children.
Large nodules and cysts accompany smaller follicular papules and pustules, from which purulent material can be expressed. Temporary hair loss over the lesions eventually results in permanent scarring and bald patches.
Perifolliculitis capitis abscedens et suffodiens is very resistant to treatment. The severity may be reduced with oral isotretinoin, antibiotics, dapsone and injected or systemic steroids. Compression of fluctuant nodules has also been reported to be of benefit.