[Janice]

Parasitic folliculitis

Parasites causing folliculitis (inflammation of a follicle) are usually small pathogens that burrow into the hair follicle to live there or lay their eggs. Mites such as Demodex folliculorum and Demodex brevis are natural parasites of the human pilo-sebaceous follicle, and Demodicosis is the name of the disease or condition caused by these parasites. These mites are found in higher concentration in areas of the body with more sebaceous glands, as well as in abundant sebum production areas such as the chest, back, temple, periorbital area and nose. Usually these mites live in our hair follicles without cuasing any problems beyond some itching, but sometimes the response of the body to these parasites can be more severe. It is believed that the mites can act by provoking a small allergic reaction in the follicle, blocking the follicle, or allowing other microorganisms to infect the skin.

The spectrum of the skin disorders due to these follicle parasites includes:

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Follicular pityriasis (skin disease characterized by epidermal shedding of flaky scales), eruptions of the scalp with or without pus
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Acne rosacea (a chronic dermatitis of the face characterized by a red or rosy coloration with deep-seated papules and pustules)
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Some cases of blepharitis (inflammation of the eyelids)
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Perioral dermatitis
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Pustular folliculitis
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Hyper-pigmented plaques (superficial elevated solid lesions greater than 1 cm)

All these conditions show rapid response to topical permethrin cream (a topical insecticide used to treat mites) or systemic ivermectin or itraconazole (where a complicating fungal infection along with the mites is suspected).