Miriam Armanious, BSc, MD candidate, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario
Joseph M. Lam, MD, FRCPC, Clinical Associate Professor, Department of Pediatrics, Associate Member, Department of Dermatology
and Skin Sciences, University of British Columbia, Vancouver, BC.

Abstract
Superficial fungal infections are a common occurrence in adults and children alike. Dermatophytes are the primary cause of these infections, which generally present as erythematous, scaling, annular lesions. Also referred to as "tinea", these infections are classified based on where they are found on the body, as different locations can have slightly different presentations and treatment requirements. This article provides an overview of these various presentations of dermatophyte infections and their risk factors, as well as recommended therapies.
Key Words: dermatophytes, fungal infections, therapies.

Introduction
Dermatophytes are a specific type of fungus that feeds on keratin. Keratin is a protein that is found on superficial skin, nails, and hair, where these infections tend to occur. Dermatophyte infections are the most common type of superficial fungal infections.¹ They are most commonly spread from person to person (anthropophilic), but can also be spread to humans from soil (geophilic), animals (zoophilic), or fomites. It is not unusual for these infections to spread from one infected part of the body to another. Dermatophyte infections do not involve mucosal surfaces. The most common pathogens in these types of infections are Microsporum, Trichophyton, and Epidermophyton.² Diagnosis is often based on clinical suspicion in addition to potassium hydroxide microscopy, fungal cultures, and sometimes Wood's lamp examination. When dermatophyte infections are treated with topical corticosteroids, they become harder to detect. This is known as tinea incognito.

Tinea Capitis
A dermatophyte infection of the scalp is referred to as tinea capitis. In North America, this is often caused by Trichophyton tonsurans. Another source is Microsporum canis, which is harboured by cats and dogs. M. canis is a common causative dermatophyte in European and Mediterranean countries.³ Tinea capitis is commonly found in the pediatric population, with a peak incidence between 3 and 9 years of age.⁴ It is most common in people of African descent. Tinea capitis can present in different ways; the scalp can be dry and flaky in some instances, while in others there can be a crusted, matted look to the hair. Tinea capitis can also be accompanied by alopecia (Figure 1). While there can be smooth areas of hair loss, usually there are patches showing a "black dot" pattern where the roots of the hairs are still present due to breakage of the overlying hair shaft. In severe cases, an abscess called a kerion can present (Figure 2). This crusting, pustular, inflammatory plaque is caused by a hypersensitivity response to fungal antigens.

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