6th July 2023

Fungal Skin Infections

Tinea Infections (Dermatophytoses) 

This refers to a skin infection caused by dermatophytes and is one of the most common causes of superficial fungal infections. Dermatophytes are fungi that require keratin for growth and therefore infect the stratum corneum, nails and hair.

Risk factors include diabetes, immunodeficiency, occlusive clothing and crowded conditions. It is more likely in children and the elderly. Dermatophyte infections present as itchy, annular lesions with raised borders. Transmission is via contact with an infected person, contaminated objects or infected animal. The feature of the fungal infection depends on the site:

Table 5: Summary of tinea infection sites and common organisms

Tinea skin infection 

Image Source: Wikimedia Commons (2012). Yeartinfection, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Yeartinfection.JPG (Accessed on: 10 March 2022).

Diagnosis can be established with skin scrapings, hair or nail clippings sent for microscopy and culture. First line management is with topical antifungals (e.g. terbinafine, clotrimazole, miconazole). Oral antifungals should be used in tinea capitis and severe or extensive disease. Oral terbinafine can cause hepatotoxicity so LFTs must be monitored.

Superficial Candida Albicans Infection 

Candida albicans is a yeast that commonly infects the skin and is a commensal organism in the GI tract. Predisposing factors include extremes of age, opposing skin folds, obesity, diabetes, immunosuppression, use of broad-spectrum antibiotics and humid environments. Diagnosis is clinical but swab samples sent for microscopy can demonstrate budding yeast cells and pseudohyphae. Superficial infection may present in a number of sites:

Table 6: Summary of candida albicans infection and its management

Oral candida albicans infection 

Image Source: Wikimedia Commons (2008). Oral thrush Aphthae Candida albicans. PHIL 1217 lores, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Oral_thrush_Aphthae_Candida_albicans._PHIL_1217_lores.jpg (Accessed on: 10 March 2022).

Pityriasis (Tinea) Versicolor

Pityriasis versicolor commonly affects teenagers and young adults and is caused by a yeast, Malassezia furfur. It presents on the trunk, neck and arms and is characterised by multiple round pink, brown or hypopigmented macules and patches with a fine scale. It may be asymptomatic or mildly itchy.

Pityriasis versicolor 

Image Source: Wikimedia Commons (2012). Tinea versicolor1, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Tinea_versicolor1.jpg (Accessed on: 10 March 2022).

Diagnosis is clinical but microscopy from skin scrapings using potassium hydroxide will demonstrate hyphae and budding cells (“spaghetti and meatballs” appearance). Wood lamp examination will demonstrate a yellow-green fluorescence. Treatment is usually needed for remission. Initial management is with an antifungal shampoo (ketoconazole 2% shampoo OD for 5/7) or cream (e.g. clotrimazole). If extensive or topical treatment is ineffective, oral antifungal such as fluconazole or itraconazole can be used. Changes in skin pigmentation can take months to resolve and relapse is common.