Tinea barbae spreading to locus minoris resistentiae

ARTICLE

Auteur(s) : Christina S Sander¹, Olaf Sander², Ayman Khatib¹, Thomas Berger^1,3

¹Division of Dermatology, Tawam Hospital, P.O.Box 15258, Al Ain, UAE
²Department of Anaesthesiology, Tawam Hosptital, Al Ain, UAE
³Department of Dermatology, University Hospital of Erlangen, Erlangen, Germany

Tinea barbae is a dermatophyte infection that affects the skin and hair follicles. We report a case of uncommon spreading of tinea barbae to the site of a skin graft on the left forearm in an immunocompetent individual. Although spreading of dermatophyte infections to a locus minoris resistentiae is a well known fact, there are no reports available demonstrating this phenomenon.

A 43-year-old United Arab Emirates (UAE) national presented to our Dermatology Clinic with development of scaly lesions on the left forearm. He had frequent contact with goats, sheep and camels. On examination he also presented with scaly plaques, pustules and papules on the right site of the face exclusively in the beard area (figure 1A). Detailed history revealed that the facial lesions had been present first. Secondly he had developed several nummular plaques on the left arm, limited to the site of previous skin grafting (figure 1B). No other skin sites were affected. The patient was immunocompetent without concomitant disease.

The well healed skin graft was done 5 years previously due to the development of a compartment syndrome after a snake bite. The man was bitten on the left index finger by an Arabian horned viper, Cerastes gasperettii, whose venom is cytotoxic and haematotoxic. He developed massive swelling of the left forearm, and a fasciotomy was performed. Mesh skin grafting, using skin from the patient’s upper thigh, was performed two weeks after the incident and healed well. Since then he had not complained of any wound healing disorder or skin infection.

By native microscopy and dermatophyte culturing, a diagnosis of skin infection of both sites by Trichophyton mentagrophytes was made. Treatment with terbinafine 250 mg/day orally for three weeks led to clinical and mycological healing of the lesions on the face and forearm after four weeks.

In dermatophyte infections it is important to examine the full integument of the patient. Larruskain et al. reported the prognostic and therapeutic significance of dermatophytosis with concurrent lesions in distant locations that occurred in 16% of the patients with dermatophytic skin infection [1]. Interestingly, in our case there was a difference in both clinical presentations that can be explained by the lack of hair follicles in the transplanted skin. Whereas in the beard area a classical zoophilic dermatophytosis invading the hair follicles was found, on the left arm, in the area of previous skin grafting, a more superficial spread was observed (figure 1).

Transplantation of skin always bears the risk of primary and secondary skin infections. In a survey analyzing skin graft loss due to infection, a rate as high as 24% was reported in general plastic surgery patients [2]. There are several case reports of rare skin infections in grafted skin. In a case of an infected diabetic foot ulcer, an infection of the grafted skin by cutaneous aspergillosis was described [3]. Also, a bacillary angiomatosis in an immunocompetent child with a grafted traumatic wound was reported [4]. Maeda et al. described a case of Nocardia brasiliensis infection on grafted skin after a trauma to the foot [5]. We demonstrated, in our case, the spreading of a Tinea barbae dermatophyte infection to grafted skin as the patient’s locus minoris resistentiae.

Acknowledgements

References

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3 Lai CS, Lin SD, Chou CK, Lin HJ. Aspergillosis complicating the grafted skin and free muscle flap in a diabetic. Plast Reconstr Surg 1993; 92: 532-6.

4 Turgut M, Alabaz D, Karakas M, Kavak M, Aksaray N, Alhan E, et al. Bacillary angiomatosis in an immunocompetent child with a grafted traumatic wound. J Dermatol 2004; 31: 844-7.

5 Maeda M, Sato M, Tozaki Y, Okumura Y, Mikami Y. Nocardia brasiliensis infection seen on grafted skin of the dorsum of a foot. Nippon Ishinkin Gakkai Zasshi 2001; 42: 137-42.