Dermatophytosis Flashcards
Define dermatophytosis.
Superficial fungal infection with varying presentation depending on site. Dermatophytes are fungal organisms that require keratin for growth.
What is the aetiology of dermatophytosis?
Some dermatophytes are spread directly from one person to another (anthropophilic organisms); others are transmitted to humans from soil (geophilic organisms), while some are spread to humans from animal hosts (zoophilic organisms).
What are risk factors for dermatophytosis?
Exposure to infected people, animals, or soil
Exposure to fomites, including hat, combs, hairbrushes, and upholstery
Chronic topical or oral corticosteroid use
HIV
Diabetes mellitus and other metabolic disorders
Occlusive clothing
Hot, humid weather
Obesity
Hyperhidrosis
Frequenting public bathing areas while barefoot
Deformities of the feet
Recurrent trauma to the skin
Summarise the epidemiology of dermatophytosis.
Estimates of the incidence and prevalence of dermatophyte infections vary.
Tinea pedis: The most common of the superficial fungal infections, occurring in up to 70% of adults.
Onychomycosis: The most prevalent condition affecting nails, accounting for approximately 50% of all nail disease.
Tinea capitis: Mainly affects pre-adolescent children, with one study reporting peak incidence in black boys under the age of 10.
Tinea corporis: Common, with highest prevalence in pre-adolescents in hot, humid climates.
Tinea cruris: Most prevalent in adolescent and adult men.
Tinea barbae: Uncommon and most likely to be found in men who have been in direct contact with infected farm animals.
What are the signs and symptoms of dermatophytosis?
History of skin, hair, or nail lesion
Skin discomfort
Scaling scalp lesions
Patchy alopecia
Erythematous, scaling skin lesions with central clearing
Erythematous, scaling rash with follicular pustules in beard or moustache
Erythematous, annular patches on face
Diffusely dry palmar surface with hyperkeratosis
Vesicles and scaling of hands
Erythematous, scaling lesions with raised border on thighs, together with pustules, vesicles, and maceration
Vesicles, pustules with or without bullae on the soles
Fissuring, maceration, and scaling in the interdigital spaces of the fourth and fifth toes
Chronically scaly, hyperkeratotic plantar skin with erythema of the soles, heels, and sides of the feet
Folliculitis with nodules
What investigations should be performed for dermatophytosis?
CLINICAL DIAGNOSIS
Potassium hydroxide (KOH) microscopy can aid when unclear clinically
What is the management for dermatophytosis?
Tinea faciale, tinea corporis, tinea cruris, tinea pedis: Topical terbinafine
Tinea capitis, tinea barbae, tinea manuum, Majocchi’s granuloma: Systemic antifungals
What are complications associated with dermatophytosis?
Kerion - Inflammatory, painful scalp mass with tinea capitis
Bacterial infection associated with tinea pedis
What is the prognosis of dermatophytosis?
Prognosis for treatment of most tinea infections is excellent. However, individuals who are immunocompromised may have persistent infection or occasionally develop invasive dermatophyte disease.
