First Report of Concomitant Tinea Faciei and Pityriasis Folliculorum: A Dermatomicrobiological Rarity

Abstract

Tinea faciei (TF) is a common dermatomicrobiological condition caused by dermatophytes involving the skin of the face but not the mustache and beard (Tinea barbae). It poses a diagnostic dilemma with its atypical clinical presentation. Pityriasis folliculorum (PF) is a dermatological condition that results in rosacea-like skin eruptions. It was previously associated with a human ectoparasitic infestation. Demodex mites (Demodex folliculorum) is a group of obligate parasites that live on the skin of mammals. These mites have been associated with various dermatological disorders, clinically termed as demodicosis. Insects have been described as potential vectors that can carry various microorganisms and especially spores of fungi. Hence, infestation by such insects may aggravate the already present skin condition, leading to secondary infections. There has been a change in the trend of dermatophytosis worldwide and infections caused by Trichophyton mentagrophytesvar.interdigitale (T. interdigitale) are increasing. Hence, there is an urgent need for a thorough investigation of an infectious etiology among various skin disorders. This is the first report of concomitant Tinea faciei and Pityriasis folliculorum involving facial skin.

Keywords: demodicosis; dermatophytosis; ectoparasitic infestation; pityriais folliculorum; t. interdigitale; tinea faciei; trichophyton mentagrophytes complex; trichophyton mentagrophytes var interdigitale.

Figure 1. Description of lesions of Tinea faciei and Pityriasis folliculorum

a. Annular erythematous lesions on the forehead with sharp margins and raised edges (arrowheads); b. Scaly plaques with papular to papulopustular lesions involving both the eyebrows, the nose and the left cheek (arrowheads)

Figure 2. Direct microscopy using KOH and modified acid-fast stain showing hyphal elements and Demodex mites

a. Direct 20% KOH preparation of the skin scrapings (extrafollicular involvement) showing Demodex mites (40X); b. Demodex mites in KOH mount showing the posterior segment with secondary striations (arrowhead); c. Demodex mite seen along with fungal elements in skin scrapings (arrowhead); d-e. KOH preparation of the skin scrapings showing a moderate number of hyaline septate hyphae, few breaking into chains of arthroconidia (arrowheads); f. Modified acid-fast staining showing Demodex folliculorum mite stained in blue color (40X). The mite is seen with two fused segments. The first segment has four-pairs of legs (arrowhead) and the posterior segment is longer, with a round opisthosomal end (arrowhead). KOH: potassium hydroxide

Figure 3. Cultural and phenotypic attributes of T. mentagrophytes complex

a. Microplate culture on PDA after two weeks showing stellate, light brown, powdery growth; b. Reddish reverse pigmentation; c. Growth on DTM agar base initially showing downy colonies; d. Urease positive; e. Lactophenol cotton blue mount of fresh colonies of T. mentagrophytes complex showing macroconidia; f. Peridial hyphae and scattered microconidia; g. Abundance of spiral hyphae and a few microconidia as observed from mature colonies.