Fungal folliculitis

As the name suggests fungal folliculitis is caused due to fungal infections. Superficial fungal infections are found in the top layers of the skin; deep fungal infections invade deeper layers of the skin. The infection from hair follicles can also spread to blood or internal organs.

The dermatophytic fungus, pityrosporum fungus and the yeast candida folliculitis are the prominent among the fungal folliculitis causes.

Dermatophytic folliculitis is caused most often by a zoophilic species, i.e. fungal species that show attraction to or affinity for animals. The condition presents as follicular pustules around a hardened erythematous (reddened) plaque. A deep fungal penetration causes a high degree of inflammation and determines the extent of hair shaft loss that occurs due to the infection.

Tinea capitis or ringworm of the head is the most important form of pediatric dermatophytic folliculitis. The clinical features of tinea capitis vary considerably depending on the species responsible for the infection. Typically, there is partial alopecia with a varying amount of inflammation.

In the non-inflammatory variants, asymmetrical lesions with short broken hair, 1 to 3 mm in length, are observed. Slight inflammation with scaling may be observed on careful inspection.

The most severe inflammatory reactions are called kerion and produce painful boggy masses studded with pustules. These lesions can result in severe hair loss and significant scarring when the disease is in advanced stages. The diagnosis of tinea capitis is established by identifying the organism in infected hairs under the microscope. A diagnosis is often confirmed by cultures.

Tinea barbae is a superficial dermatophytic infection that is limited to the bearded areas of the face and neck and occurs almost exclusively in older adolescent and adult males. The clinical presentation of tinea barbae includes deep folliculitis, red inflammatory papules and pustules with exudation, crusting and associated hair shaft loss. The two main species causing the infection are T. mentagrophytes and T. verrucosum.

Pityrosporum folliculitis is caused by pityrosporum yeasts resulting in an itchy eruption. The lesions are reddish follicular papules and pustules located mainly on the upper back, shoulders and chest.
Candida folliculitis is caused by the Candida species, ubiquitous fungi that most commonly affect humans.