INTRODUCTION
Pityriasis folliculorum, coined as rosacea-like demodicosis, is a dry type of rosacea with pathogenesis involving extensive infestation of Demodex folliculorum.1-7 D. folliculorum is an obligate parasite that resides within the hair follicles of the pilosebaceous glands of the skin, inhabiting 80%-100% of individuals over 50 years old.3-4,7 The clinical presentation involves generalized facial flushing and small sebaceous hair follicles plugged with dry, white scale, sometimes accompanied with visible pustular inflammation.1,6-9Although this skin condition is difficult to manage, treatment of choice for demodicosis is oral ivermectin, an anaricidal that has anti-inflammatory and anti-parasitic properties, with activity against endoparasites and ectoparasites such as D. folliculorum.7,10 Topical ivermectin 1% cream has recently been shown to be effective for treatment of rosacea.11-13 Here we present the case of a woman with pityriasis folliculorum successfully treated with ivermectin 1% cream with no significant complications.
CASE REPORT
A 38-year-old woman presented to dermatology clinic with complaint of “rosacea” that she had had for 3 years. She described persistent redness of the central face and forehead with increased flushing from exercise and alcohol intake. She did not have any previous treatment. She used facial moisturizer and mild soaps, but no sunscreen. She had no known history of immunodeficiency.Skin exam demonstrated diffuse facial erythema with follicular spicules, pink to red rough patches at the central face and forehead, and a single micropustule on the left cheek. A diagnosis of pityriasis folliculorum was given. Ivermectin 1% cream was prescribed, used as a thin film applied to the entire face daily. Daily sunscreen use with SPF 30 or higher was also recommended. Scraping was not done to detect Demodex mites.At three-month follow up, the patient noted improved facial redness and endorsed great improvement of skin texture with the use of ivermectin 1% cream. Skin exam at this time revealed significant improvement of the rough skin texture and follicular spicules seen previously. Mild erythema was present on the cheeks, forehead, and nose. The cheeks were also notable for a few inflammatory pink papules consistent with papulopustular rosacea that had not been identified at initial presentation. Ivermectin 1% cream was refilled and Doxycycline 100 mg twice daily was added to the regimen to treat the papulopustular lesions. Pictures of pre- and post-treatment are not available.
DISCUSSION
Pityriasis folliculorum, later termed rosacea-like demodicosis by Ayres and Ayres, has been considered to be a dry type of rosacea manifesting with extensive proliferation of Demodex folliculorum.1-2 In a prior study, a single removed hair follicle showed a substantial number of Demodex mites in a patient with this skin condition.5 Other skin abnormalities that involve increased habitation by Demodex species when compared to control groups include blepharitis, pustular folliculitis, acne, perioral dermatitis, and demodicosis gravis.3-5,14-15 The degree of Demodex species infestation can contribute to the development of rosacea by initiating inflammation, inhibiting immune response, serving as an obstruction to hair follicles, and acting as a reservoir for bacterial accumulation.4 Demodex mites are most commonly located on the face in the vellus-sebaceous hair follicles, particularly the nose and temple.15The typical appearance of pityriasis folliculorum is diffuse facial erythema with white-yellow minuscule, distinct scales of sebaceous hair follicles that are often plugged, with or without minimal inflammation often presenting as small superficial vesiculopustules.1,6-9 Associated symptoms often include pruritis and rough, sensitive skin.6 Other atypical presentations of D. folliculorum include acneiform lesions, or facial pruritis with
