Types of eosinophilic folliculitis
There are several variants of eosinophilic folliculitis, which is also known as ‘eosinophilic pustular folliculitis’ or ‘Ofuji disease’. The name is due to skin biopsy finding of eosinophils (a type of immune cell) around hair follicles.
All of them present with itchy papules (bumps) or pustules. Eosinophilic folliculitis is rare and more often affects males than females. Variants include:
- Classic type – this occurs most commonly in Japan
- Eosinophilic folliculitis associated with advanced Human Immunodeficiency Virus (HIV) infection
- Infantile type
- Cancer-associated variant
- Medication-associated variant
What does eosinophilic folliculitis look like?
Eosinophilic folliculitis presents with red or skin-coloured dome shaped papules (bumps) and pustules. It may look rather like acne or other forms of folliculitis. These mostly appear on the face, scalp, neck and trunk and may persist for weeks or months. Less commonly urticarial lesions are seen (these are larger red irritable wheal-like patches similar to urticaria). Palms and soles may rarely develop similar papules and pustules, but in such cases the condition should not be called ‘folliculitis’ as there are no follicles in these areas.
Eosinophilic folliculitis is often a feature of immunodeficiency. Eosinophilic folliculitis associated with HIV infection appears as levels of CD4 lymphocyte cells drop below 300 cells/mm3, a level at which there is an increased risk of a secondary opportunistic infection. It has also been reported after bone marrow transplantation before the immune system is back to normal functioning, and in some individuals with inherited immune deficiencies.
Skin biopsy reveals eosinophils under the skin surface and around the hair follicles and sebaceous glands. In many cases blood tests show a mild rise in eosinophil cells and immunoglobulin-E (IgE), and reduced IgG and IgA levels.
What is the cause of eosinophilic folliculitis of HIV?
The cause is not known. Immunodeficiency appears to lead to increased risk of allergic-type skin diseases. There is no proof that bacterial, fungal or viral secondary infection is the cause, although some researchers have postulated overgrowth of Malassezia or Demodex (the hair follicle mite) might be involved. Another theory is that there is a change in the immune system causing eosinophils to attack the sebum (oils produced in the skin) of sebaceous gland cell.
What is the treatment?
In patients with HIV, eosinophilic folliculitis is likely to improve or resolve with HAART (Highly Active Anti-Retroviral Treatment).
Other treatments that may be effective include:
- indomethacin (nonsteroidal anti-inflammatory)
- topical steroids
- calcineurin inhibitors such as tacrolimus ointment
- oral antihistamines such as cetirizine
- tetracycline antibiotics
- Other antibiotics including metronidazole
- permethrin cream (topical insecticide)