Eosinophilic pustular folliculitis

A variety of treatment options for eosinophilic pustular folliculitis (EPF) have been described with variable results.^[1] Individualized therapy should be tailored to the type of EPF present.^[2]

The effectiveness of oral nonsteroidal anti-inflammatory drugs (NSAIDs) is well established for many cases of classic EPF (more than 70%), but the reason why remains unknown. There are cases in which NSAIDs are not effective.^[3] For cases of classic EPF, common NSAID options for treatment include indomethacin (orally or topically) and acemetacin. Naproxen has also been used with some success. For classic cases that are not responsive to NSAIDs, other treatment options include:^[1][2]

• dapsone
• topical and systemic steroids
• isotretinoin
• itraconazole
• permethrin
• interferon
• antibiotics

Additional treatment options that may improve symptoms include:^[1][4][2]

• narrowband UVB phototherapy
• ultraviolet therapy with ultraviolet B or with ultraviolet A
• Psoralen plus ultraviolet A (PUVA)
• calcineurin inhibitors such as tacrolimus ointment
• colchicine
• transdermal nicotine patches

The infantile form tends to respond well to topical corticosteroid therapy. It is important to recognize that this form typically resolves on it's own before age 3 in over 80% of cases, so observation or avoiding aggressive treatment is often recommended.^[2]

In people with HIV-associated EPF, antiretroviral therapy tends to greatly diminish symptoms or even eliminate the condition.^[1]

Because the underlying cause of eosinophilic pustular folliculitis (EPF) is not known and its nature is poorly understood, it is difficult to categorize the condition. To our knowledge, EPF has not been described specifically as an autoimmune disease or an allergic disorder. Several journal articles have described EPF more broadly as an "inflammatory" disorder.^[5][3][6] While some inflammatory disorders are also autoimmune disorders, others are not. When the cause of EPF is better understood, researchers may be able to better categorize the condition. 

That being said, many researchers do suspect that the immune system plays a key role in developing the condition. A growing number of reports on EPF in people with weakened immune systems indicates the contribution of a disturbed immune system.^[3] It has been suggested that in both children and adults, EPF should be viewed as a possible cutaneous (skin) sign of immunosuppression. In contrast to autoimmunity (when the body mistakenly attacks healthy cells), immunosuppression makes the immune system less able to detect and destroy infections. However, EPF is also seen in people with normal immune status.^[2]

Proposed triggers or causes of EPF have included:^[1]

• an exaggerated reaction to dermatophytes (skin fungi) or saprophytic fungi, in association with a disordered immune system. This theory is supported by the effectiveness of oral itraconazole therapy in some people with EPF.^[1]
• demodex, a mite that lives in the hair follicle, as a possible trigger^[1]
• a combination of Pityrosporum (yeast) and demodex
• a change in the immune system causing eosinophils to attack the sebum (oils produced in the skin) of sebaceous gland cells.^[4]

The long-term outlook (prognosis) for people with eosinophilic pustular folliculitis (EPF) depends on the type of EPF present (classic, infantile, or immunosuppression-associated).

Classic EPF, which occurs mainly in adults, is generally chronic and recurrent but benign. Individual lesions typically last more than 1-2 weeks, and relapse every 3-4 weeks. Except for skin involvement, people with classic EPF are generally in good health with no systemic symptoms.

Infantile EPF generally also runs a benign course, and resolves on its own by 3 years of age in over 80% of cases. It is important to recognize that this form is self-limiting so as to avoid unnecessary aggressive treatment in affected infants. Children with this form also generally remain in good health without associated problems, although a possible association with atopy (tendency to develop allergies) has been speculated.

The immunosuppression-associated type of EPF is mainly associated with HIV infection, hematological malignancy (blood cancers), or other cancers, so recognizing that a person has this form of EPF is important. The overall prognosis beyond the skin symptoms largely depends on the prognosis associated with the underlying condition.^[6]

To our knowledge, eosinophilic pustular folliculitis (EPF) does not weaken the immune system. On the contrary, the development of EPF may indicate that a person's immune system is compromised. However, EPF is also seen in people with apparently normal immune status.^[2]