Med. Mycol. J. Vol.Med. 57E, Mycol. E 59 J. − Vol. E 61, 57（No. 2016 3）, 2016 E59 ISSN 2185 − 6486

Short Report A Case of due to tonsurans that Manifested as Impetigo

Harunari Shimoyama, Chikako Nakashima, Midori Hase and Yoshihiro Sei

Department of , Teikyo University School of Medicine Mizonokuchi Hospital

ABSTRACT

A 41-year-old man visited our dermatology clinic because an eruption, which was resistant to steroid ointment treatment, had appeared on his right forearm. An oval, soybean-sized erythematous infiltrated lesion with scales and crusts was located in the central part of the extensor surface of the right forearm and showed partial erosion with attached yellow crusts. The lesion had an impetigo-like appearance. Fungal elements were confirmed from the scales by KOH examination and the fungus was identified as by fungal culture and molecular method. Clinical features of T. tonsurans infection vary, wherein some patients have strong inflammatory manifestations, while others remain as asymptomatic carriers. Especially at the early stage of the infection, diagnosis is difficult because it is often misdiagnosed as eczema. We report a case of T. tonsurans infection that had impetigo-like appearance. We also studied the mechanism of the disease. Key words：Trichophyton tonsurans, impetigo-like appearance, KOH examination

on the right forearm. He was healthy and had Introduction been serving as a judo coach for young athletes twice a week. As history of the present illness, an Trichophyton tonsurans infection was first eruption associated with slight itch had appeared brought from abroad to Japan through interna- on the right forearm four months earlier. He had tional competitions of combat sports around the visited two local hospitals, but since it tested year 2000. Subsequent outbreaks among the negative on a fungal examination, steroid oint- combat sports participants were then reported. ment was prescribed. His symptoms, however did Following an epidemic among friends and families not improve, so he visited our department. of combat sports participants, the disease has On examination, an oval, soybean-sized erythe- now become prevalent nationwide1−3）. matous infiltrated lesion with scales and crusts Diagnosis is difficult since this disease presents was found almost in the central part of the various clinical features. Recently, we encoun- extensor surface of the right forearm, and it tered a case of tinea corporis presenting with showed partial erosion with yellow crusts peculiar clinical features and having impetigo-like attached（Fig. 1）. Fungal elements were con- appearance, and we report this case and discuss firmed from the scales through KOH examination details on the clinical types of tinea. （Fig. 2）. No fungal elements were found in the villous hairs. Case Mycological examination A 41-year-old male company employee visited our department complaining of an itchy eruption The fungal culture taken from the scales that

Address for correspondence : Harunari Shimoyama Department of Dermatology, Teikyo University School of Medicine Mizonokuchi Hospital, Mizonokuchi 3-8-3, Takatsu-ku, Kawasaski-shi, Kanagawa, 213-8507, Japan Received : 4, November 2015, Accepted: 22, March 2016 E-mail : [email protected] E60 Medical Journal Volume 57, Number 3, 2016

Fig. 1．An oval, soybean-sized erythematous Fig. 2．Fungal elements were confirmed from the infiltrated lesion with scales and crusts was scales by KOH examination. located almost in the central part of the extensor surface of the right forearm and showed partial erosion with yellow crusts attached, presenting a impetigo-like appearance.

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Fig. 3a, b．The growth of a colony with white fluffy surface and reddish brown color on the reverse side was observed on Mycosel agar.

reddish brown color on the reverse side was observed on Mycosel agar（Fig. 3a, b）. Microsco- pic morphology showed teardrop- and club- shaped microconidia, which were not stained by lactophenol cotton blue, were observed along the hyphae or on short conidiophores（Fig. 4）. DNA sequence analysis of the internal transcribed spacer（ITS）region was performed. The ITS region of this isolate showed 100 % similarity to that of T. tonsurans（AB220044）. It was also identified as T. tonsurans based on the morpholo- Fig. 4．Microscopic morphology showed teardrop- gical features. and club-shaped microconidia, which were not stained by lactophenol cotton blue, observed along the hyphae or on short conidiophores. Treatment

Considering that the infection is tinea corporis erupted was positive, while a hairbrush culture caused by T. tonsurans based on the sports method from the scalp indicated negative results. background of the patient, we initiated oral Growth of a colony with white fluffy surface and terbinafine treatment at 125 mg. The eruption Med. Mycol. J. Vol. 57（No. 3）, 2016 E61

improved following a four-weekoral administra- textbook 5）, tinea circinata is the typical type, tion of terbinafine. There has been no recurrence whereas fungal （Majocchi granuloma） so far. and tinea incognito are included in the atypical type. In our case, it is unclear whether a granulo- Discussion ma was formed because a was not performed, but we chose systemic therapy with Clinical features of tinea corporis depend on the terbinafine because of the ability of this fungus to anatomic sites of eruptions（stratum corneum, easily invade hair in the early stage of the hair, nails, and subcutaneous tissue）, the hostʼs infection and a history of incorrect administration immunological reaction（local and systemic）, and of steroid ointment. Nevertheless, we reaffirmed the species of the dermatophytes4, 5）. Tinea cor- the importance of the KOH examination for poris, which is one type of , have incurable eruptions through our case. clinical features that vary from typical, circular, sharply circumscribed erythema and to Acknowledgements atypical symptoms, depending on the previously described three conditions. Furthermore, there We thankUmeda Y and MakimuraK for help in are more causative organisms for tinea corporis molecular biological identification. compared with those of other disease types. Specifically, the symptoms of T. tonsurans Conflict of Interest infection are mainly and tinea corporis. The former has three clinical types All authors declare no conflict of interest. （seborrheic type, blackdot ringworm type, and celsi type）; whereas the latter includes the References tinea circinata type, eczema marginatum type, and plague-like type, and a remarkable feature is 1）Mochizuki T, Tanabe H, Wakasa A, Kawasaki M, that it is an -type that can Anzawa K, Ishizaki H: Survey of Trichophyton easily invade hair. The symptoms vary among tonsurans infection in Japan − molecular epide- miology and factors affecting adequate hairbrush patients, with some showing strong inflammatory sampling. Jpn J Med Mycol 47: 57-61, 2006. manifestations while others remaining as asymp- 2）Fujita S, Mochizuki T: A case of black dot tomatic carriers. In the early stage of the infection ringworm on the right forearm caused by it is often misdiagnosed as eczema and thus Trichophyton tonsurans. Jpn J Med Mycol 48: overlooked. More problematic is the fact that 91-95, 2007. eruptions can spontaneously heal without care, 3）Shiraki Y, Hiruma M, Hirose N, Ikeda S: Commonly affected body sites in 92 Japanese combat sports and patients carry the fungus on their scalps4, 6, 7）. participants with Trichophyton tonsurans infec- In our case, the eruption appeared on the tion. Mycoses 52: 339-342, 2008. extensor surface of the right forearm, which is 4）Verma S, Heffernan MP: Superficial fungal infec- considered as a site where minor traumas can tion, , : In Fitzpatrickʼs Dermatol- easily occur. We assumed it occurred because of ogy in General Medicine, 7th ed.（Wollf K, Gold- rubbing with the sleeve of the judo uniform3, 5, 6）. smith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ ed）, pp. 1807-1821, Mc G raw-Hill, Ohio, 2007. Furthermore, both forearms of judo playing males 5）James WD, Berger TG, Elston DM: Disease are usually hairy, and the strong affinity of the Resulting from Fungi and Yeasts. In Andrewsʼ fungus to hair tissue is considered one of the Disease of the Skin 11th ed, pp. 292-293, W. B. causes for disease formation. Saunders, Philadelphia, 2011. The eruption in our case was an impetigo-like 6）Hay RJ, Moore MK: Dermatophytosis. In Rookʼ s lesion, not a typical tinea circinata type lesion. Textbookof Dermatology 7th ed.（Burns T, Breathnach S, Cox N, Griffiths C ed）, Vol.2, pp.31, Since the hairbrush culture from the scalp was 19-31, 55, Blackwell Science, Oregon, 2004. negative, it was considered a symptom of the 7）Ogawa Y, Hiruma M: Dermatophytosis: a summary early stage of the infection2）. The clinical types of of as a proposal for future tinea corporis are classified differently by diffe- revision of the guidelines. Jpn J Med Mycol 50: rent textbooks, but according to Andrewʼ s 199-205, 2009.