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.
It is characterised by small, very itchy pustules within 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 Propionibacterium acnes, but in severe cases, also Staphylococcus aureus)
- Yeasts (Malassezia species)
- Mites (Demodex folliculorum)
The scalp 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:
- Topical antibiotics e.g. 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.
This 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.