Snapshot Dx Quiz: December 2016 DETAILED ANSWERS Nayoung Lee, MD and Mariya Miteva, MD Department of Dermatology and Cutaneous Surgery, University of Miami L. Miller School of Medicine

Images credit to Mariya Miteva, University of Miami

1.

What is your diagnosis based on the clinical and trichoscopic image?

a.

Alopecia areata

b.

Trichotillomania

c.

Tinea capitis

d.

Traction alopecia

e.

Congenital triangular alopecia

ANSWER: c) Tinea capitis is most commonly caused by Trichophyton tonsurans in the United States (Mirmirani and Tucker, 2013) and only sporadically by Microsporum canis, acquired via contact with infected puppies and kittens. It can often present with alopecia in patches, as depicted here, or a more diffuse alopecia involving the entire scalp (Elewski, 2012). If untreated, it can lead to significant scarring with permanent hair loss. Alopecia due to dermatophyte infection can be differentiated from other causes of alopecia using dermoscopy of the scalp (trichoscopy). Trichoscopic clues to the diagnosis of tinea capitis include comma hairs, which are curved, broken hair shafts reported to be associated with Microsporum canis infections (Slowinska et a1.,2008), and corkscrew hairs, seen in both Microsporum and Trichophyton infections (Arenas et al., 2010). Additional clues include dystrophic broken hairs (Hughes et al., 2011). Discussion of incorrect answers a) Alopecia areata most commonly presents as discrete circular patches of non-scarring alopecia. Hairs with broader distal ends and tapering proximal ends, termed “exclamation point” hairs, can be seen (Elewski, 2012). The most common dermoscopic features include yellow dots, black dots, broken hairs, coudability hairs (hairs that are normal in length but have narrowed proximal ends), and clustered short vellus hairs (Inui et al., 2008). Yellow dots may contain no hair or miniaturized or dystrophic hair and are a sensitive marker for alopecia areata (Ross et al., 2006). Black dots and exclamation mark hairs correlate with disease activity, whereas yellow dots and vellus hairs correlate with disease severity (Inui et al., 2008). b) Trichotillomania is a self-induced condition that leads to patches of non-scarring alopecia, which clinically mimics alopecia areata. The patches of hair loss, however, often have geometric

shapes with irregular borders, and contain hairs of varying lengths. Dermoscopy reveals findings similar to those seen in alopecia areata, such as broken hairs, black dots, and yellow dots (Inui et al., 2008). The presence of exclamation hairs is more suggestive of alopecia areata, and coiled hairs are more suggestive of trichotillomania (Miteva and Tosti, 2012). New variations of broken hairs (flame hairs, V-sign, hook hairs, hair powder, tulip hairs) were recently described in trichotillomania (Rakowska et al., 2014). d) Traction alopecia is a form of non-scarring alopecia most commonly caused by hairstyling practices of African American women that can become a scarring alopecia over time. Patients typically present with bitemporal or frontal hair loss (Elewski, 2012). In earlier stages of traction alopecia, dermoscopy reveals hair casts enveloping the proximal portion of the hair shafts located at the periphery of the patches of alopecia (Miteva and Tosti, 2012). e) Congenital triangular alopecia presents at birth or in the first decade of life, and the typical clinical presentation is hair loss in a lancet-shaped distribution from the temporal hairline extending superiorly and posteriorly (Elewski, 2012). These lancet-shaped patches of alopecia contain long vellus hairs and no terminal hairs on dermoscopy (Iorizzo et al., 2008).

2.

Which of the following answers is TRUE?

a.

Tinea capitis is more common in adults than in children.

b.

Trichophyton tonsurans, Microsporum canis, and Epidermophyton floccosum are the most common causative agents in tinea capitis in children.

c.

The sebaceous glands are underdeveloped in children at prepubertal age.

d.

The antifungal special stains are 100% positive in scalp biopsies from inflammatory tinea capitis (kerion).

e.

Griseofulvin and terbinafine are equally effective in children with tinea capitis caused by Trichophyton spp. and Microsporum spp.

ANSWER: c.) The sebaceous glands have a fair size and the sebum production is high at birth (Pochi et al., 1979). They involute into small structures (mantle) in the following months due to the decrease of maternal androgens. At puberty, androgens such as 5α-dihydrotestosterone (DHT) lead to sebaceous gland activation and increased sebum production (Elewski, 2012). Sebum is known to have an inhibitory effect on the growth of dermatophytes (Elewski, 2012). Studies by Jo et al. demonstrated that the microbiome composition of prepubertal skin differs greatly from that of postpubertal skin. Adult skin was found to be predominately populated by the obligate lipophilic Malessezia species, whereas prepubertal skin was found to be colonized by Malessezia species as well as other diverse species of fungi, including common dermatophytes. They proposed that this difference could be attributed to the differences in sebum production between the two age groups (Jo et al., 2016).

Discussion of incorrect answers a) In general, dermatophytosis is most common in postpubertal patients, with the exception of tinea capitis, which is more commonly seen in children (Elewski, 2012). b) Trichophyton tonsurans is the most common causal organism of tinea capitis, representing greater than 90% of cases, followed by Microsporum canis (Elewski, 2012). Less common

causes of tinea capitis in the United States include T. violaceum, which is endemic in Africa. M. audouinii has also been isolated in patients with tinea capitis in Europe (Elewski, 2012). Epidermophyton floccosum is one of the most common causes of tinea pedis, tinea manuum, tinea unguium and tinea cruris but is not involved in tinea capitis (Elewski, 2012). d) A kerion represents a hypersensitivity reaction to dermatophytes, leading to tender, boggy plaques on the scalp with purulent discharge and overlying alopecia. It is most commonly caused by Trichophyton species, most commonly T. mentagrophytes. In a study by Isa-Isa et al., four histopathologic patterns were described for kerion, including suppurative folliculitis, suppurative folliculitis with suppurative dermatitis, suppurative folliculitis with suppurative and granulomatous dermatitis, suppurative and granulomatous dermatitis with fibrosing dermatitis (Isa-Isa et al., 2010). With the latter two patterns, which encompassed half of the patients with kerion, the PAS stains were negative for fungal elements (Isa-Isa et al., 2010). e) A randomized controlled trial by Elewski et al. revealed that terbinafine had higher mycologic, clinical and complete cure rates for pediatric tinea capitis caused by T. tonsurans compared to griseofulvin (Elewski et al., 2008). In contrast, children with tinea capitis caused by Microsporum had higher cure rates with griseofulvin when compared with terbinafine, according to a meta-analysis of two studies that demonstrated a 50.9% cure rate with griseofulvin and a 34.7% cure rate with terbinafine (Chen et al., 2016).

3.

Which of the following answers is FALSE according to the article by Jo et al.?

a.

Malassezia predominates on the skin of adults based on ITS1 sequencing analysis in samples obtained from nine skin sites in adults and children.

b.

Diverse Ascomycota fungi constitute commensal flora in children.

c.

Colonization of Malassezia in the nares is less predominant in children compared to adults.

d.

Cryptoccocus relative abundancies are significantly higher in girls.

e.

Malassezia globosa is the only predominant Malassezia spp. in children that is identified independent of body site.

ANSWER: d).

Jo et al. analyzed the composition of fungal organisms on different types of skin by sequencing the fungal internal transcribed spacer 1 (ITS1) sequence, which is a taxonomic signature that can identify the genus, and found that Epicoccum and Cryptococcus genera were enriched in sebaceous sites of boys, whereas Malassezia was found in higher frequency in girls (Joet al., 2016).

Discussion of incorrect answers a) Jo et al. collected samples from nine sites, including external auditory canal, forehead, occiput, retroauricular crease, back, manubrium, antecubital fossa, inguinal crease, volar forearm, and nares. Analysis of the fungal diversity by ITS1 sequencing revealed that compared with samples collected from children, those collected from adults were more enriched for Malassezia (Jo et al., 2016). A previous study using real-time PCR to analyze the prevalence of Malassezia in 770 Japanese patients has also shown that Malassezia was present at lower frequencies in prepubertal skin than in adult skin (Sugita et al., 2010). b) The skin flora of children instead consisted of a more diverse group of Ascomycota fungi, including Aspergillus, Epicoccum and Phoma. Ascomycota fungi represented greater than 5% of

the commensal flora in 40.2% of the samples obtained from children versus 9.5% of those obtained from adults (Jo et al., 2016). c) Malassezia was detected in 56.1% of nares samples obtained from children versus 92.3% of those obtained from adults (Jo et al., 2016). Malassezia is an obligatory lipophilic yeast with a predilection for sebaceous skin. Though considered part of the normal flora of human skin, Malassezia can cause disease when it transitions into the mycelial form from the yeast form. This change can be triggered by high temperature or humidity, as well as other factors such as oily skin, excessive sweating, immunosuppression, nutritional deficiency, pregnancy and corticosteroid use (Elewski, 2012). The genus Malassezia comprises of 14 species, some of which have been implicated in a variety of conditions, such as pityriasis versicolor, seborrheic dermatitis, and neonatal cephalic pustulosis. e) Previous studies have demonstrated a prevalence of M. restricta in the sebaceous sites located on the head such as the external auditory canal, forehead, and retroauricular crease, and a prevalence of M. globosa on the occiput and back (Findley et al., 2013). Similar to these findings, Jo et al. also found enrichment of M. restricta on adult samples obtained from the external auditory canal, forehead, and retroauricular crease and of M. globosa on adult samples from the back, occiput and manubrium. However, although M. restricta was detected on samples from children, M. globosa predominated on prepubertal samples from all body sites (Jo et al., 2016).

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