Seborrheic Dermatitis and Scarring: Seborrheic Folliculitis

Can a seborrheic dermatitis lead to a scarring alopecia-like phenomenon?

In 2015, Australian researchers reported an interesting article in the Australasian Journal of Dermatology suggesting the possibility of a low grade folliculitis which ultimately leads to development of a scarring alopecia.

The study described 56 patients (35 female and 21 male, age range late teens to late 70s) with a seborrheic dermatitis like presentation that was associated with a scarring alopecia. They termed the condition “seborrheic folliculitis.” These patients presented clinically with a red, itchy scalp (some patients) along with a diffuse or patchy dandruff like presentation. Shedding of telogen hairs was a feature.

Perifollicular parakeratotic scale was noted along with variable scalp erythema, and perifollicular prominence. Dermoscopy showed perifollicular hyperkeratosis and increased vascularity in the perifollicular areas. Pathology showed an absence of lichenoid change and there was a mild interfollicular fibrosis much like is seen in folliculitis decalvans (although too mild for typical folliculitis decalvans).  Spongiosis of the follicular epitheilium was noted along with a perivascular and perifollicular infiltrate of lymphocytes. Treatment was successful in many patients with tar shampoos and doxycycline. 

Here is one such example of a "seborrheic folliculitis" in a patient with androgenetic alopecia. Scarring is present and focal areas devoid of hair can be found on the scalp.

Reference

Pitney L et al. Is seborrhoeic dermatitis associated with a diffuse, low-grade folliculitis and progressive cicatricial alopecia? Australas J Dermatol 2016; 57(3):e105-7.