Tinea Infections and Treatment

Study Notes

Tinea incognito: a type of fungal infection that can be misdiagnosed due to its non-classical presentation
Tinea barbae: a ringworm infection that affects the beard, mainly in adults in contact with farm animals
- Lesions may present as kerion or tinea circinata, mostly unilateral
- Treatment: oral and topical antifungals
Tinea cruris: a ringworm infection that affects the groin, mostly in men on upper and inner surfaces of the thighs
- Clinical picture: small erythematous, scaly patch that spreads peripherally and partly clears in the center, edge is well defined with papules, vesicles or pustules
- Itching is common
- Differential diagnosis: erythrasma, seborrheic dermatitis, flexural psoriasis, simple intertrigo, candidal intertrigo, and streptococcal intertrigo
- Treatment: drying the lesions, specific topical and oral antifungals
Tinea pedis: a ringworm infection that affects the feet, also known as athlete's foot
- Most common fungal infection, more common in adult males
- Predisposing factors: wearing tight shoes, communal showers, swimming baths, and hyperhydrosis
- Clinical varieties: interdigital, squamous hyperkeratotic, and vesiculobullous
- Patient may complain of itching, bad smell, or secondary bacterial infection

Fungal infections can be divided into superficial or deep (systemic) infections
Superficial infections are restricted to skin and its appendages, while deep infections are usually of systemic nature with occasional involvement of skin
Fungal infections can be caused by:
- Dermatophytes: cause superficial infections, classified into microsporum, trichophyton, and epidermophyton
- Yeasts: e.g. malassezia furfur (causes pityriasis versicolor) and candida albicans

Mainly affects school children, more common in boys than girls
Main causative fungi in Egypt: trichophyton violaceum and microsporum canis
Clinical picture:
- Scaly type: single or multiple scaly patches, often circular in shape, with numerous broken-off hairs
- Kerion (inflammatory type): caused by animal fungi, presented as boggy indurated swellings with crusting and loose hairs
- Black-dot type: bald patches with formation of black dots as the affected hair breaks at the surface of the scalp
- Favus: caused by trichophyton schoenleinii, characterized by yellowish, cup-shaped crusts (scutula) with a distinctive mousy odor
Modes of infection: direct contact with infected child, indirect through use of patient's fomites
Diagnosis: clinical, Wood's light examination, direct microscopic examination, and culture
Treatment: topical and systemic antifungals