Fungal Skin Infections
Types of skin fungal infections include: {Dermatophytes (Tinea) and Yeast infections (Pityriasis and Candidiasis)}
Tinea corporis (ringworm): annular, red, scaly, pruritic patch with central clearing and an active border.
Tinea capitis (ringworm of the scalp): itching, scaling and alopecia. May progress to Kerion which needs aggressive treatment.
Tinea cruris (jock itch): involves the portion of the upper thigh opposite the scrotum.
Tinea pedis (athlete's foot): scaling, peeling, and erythema between the toes which can spread to other areas of the foot.
Tinea unguium (onychomycosis): thickened, brittle, discolored nails.
Tinea manuum (ringworm of the hand) is also responsible for the "Two feet, one hand syndrome”.
Tinea barbae (Barber's itch or ringworm of the beard)
Tinea incognito: is a fungal infection of the skin that generally looks odd for a typical tinea infection with blurred edges, and it appears to have florid growth after steroid application.
Candida (yeast): glazed, shiny, itchy, red especially at sites of skin-to-skin contact. Satellite yellow fluid-filled pustules a the edge of the confluent eruption area. Candida can also cause onychomycosis.
Pityriasis versicolor (Malassezia furfur): round and scaly both hypopigmented and hyperpigmented itchy red lesions.
Diagnose by KOH preparation of skin/nail scraping. Interpretation of KOH preparation mount as following:
- Fungal hyphae (dermatophytes and molds)
- Clustered and thick-walled small yeast cells with short filaments (Malassezia sp.)
- Budding yeast cells and pseudohyphae (Candida sp.).
Treatment of skin fungal infections:
All Tineas except capitis and unguium can be treated with topical creams such as terbinafine (Lamisil), clomitrazole (Lomtrin AF) and butenafine (Lotrimin Ultra).
Tinea capitis and Tinea onychomycosis will need oral terbinafine. 6 weeks for capitis and fingernails and 12 weeks for toenails. Kerion (severe capitis) will need prompt oral griseofulvin which can be switched to terbinafine if trichophyton is found. Treat tinea capitis patients and their asymptomatic close contacts with a sporicidal shampoo, such as 2.5% selenium sulfide or 2% ketoconazole, for two to four weeks to decrease infectivity and eliminate spores.
Topical nystatin or miconazole for skin candida.
Don't prescribe oral antifungal therapy for suspected nail fungus without confirmation of fungal infection. Obtain baseline AST, ALT and CBC. Obtain CBC every 6 weeks for the duration of the treatment.
Don't prescribe fluconazole for patients with hepatic impairment.
This post covers the points you need to know for your board exams as well as for teaching residents on the daily rounds. Medical professionals can't use the information here to treat their patients nor people can use the information her to treat themselves. If you are having any medical issues, contact your local emergency services. Please refer to your doctor for medical advice.