Topical treatment

The most commonly used treatments are the imidazole preparations, such as clotrimazole and miconazole (two to

Microsporum ringworm

Microsporum—Wood's light

Tinea incognito

Microsporum—Wood's light

Tinea incognito

Candida albicans

Candida albicans

Candida organisms

four weeks) and also topical terbinafine (one to two weeks). The polyenes, nystatin, and amphotericin B are also effective against yeast infection. For damp macerated skin dusting powders may be helpful. In toe web infections a mixture of micro-organisms including dermatophytes and Gram negative bacteria may be present and both require treatment.

Systemic treatment

It is important to confirm the diagnosis from skin scrapings before starting treatment. Terbinafine is a very effective fungicidal drug. It is taken in a dosage of 250 mg once daily for two to six weeks for skin infections, six weeks for finger nail or three months for toenail infections. It is only approved for use in children in some countries. Blood monitoring is only advised in patients with liver disease or impaired renal function. Pregnancy and lactation are relative contraindications. There have been reports of headaches, taste disturbances and, very rarely, liver dysfunction.

Triazole preparations such as itraconazole are effective in both dermatophyte and yeast infections. Cases of liver damage have rarely been reported. Fluconazole is effective in yeast infections. Some drugs interact with azole drugs, the main ones being terfenadine, astemizole, digoxin, midazolam, cyclosporin, tacrolimus, and anticoagulants.

Griseofulvin is mainly used for tinea capitis. The duration of treatment is six to eight weeks for infections of the scalp. The dose is 10-20 mg/kg for children, taken with food. Contraindications to griseofulvin are severe liver disease and porphyrias. The drug interacts with the coumarin anticoagulants.

In countries without access to these drugs simple measures such as antiseptic paints—Neutral Red or Castellan's paint— can be used. Whitfield's ointment (benzoic acid ointment) is easily prepared and is reasonably effective for fungal infections.

Principles of diagnosis and treatment

• Consider a fungal infection in any patient where isolated, itching, dry, and scaling lesions occur without any apparent reason—for example, if there is no previous history of eczema. Lesions due to fungal infection are often asymmetrical

• Skin scrapings or clippings should be sent to the laboratory from lesions, nails, or hair. The skin scales should be removed by scraping the edge of the lesion with a scalpel held at right angles to the skin on to a piece of dark paper—transport packs are available commercially. Clippings can be taken from the nails and as much material as possible should be taken from the nail including subungual debris. Laboratories will report first on the direct microscopy of the material examined after treatment with 10% potassium hydroxide but culture results take at least two weeks

• Lesions to which steroids have been applied are often quite atypical because the normal inflammatory response is suppressed—tinea incognito. The patient often states that the treatment controls the itch but the rash persists and may change into a tender form of folliculitis. In such cases microscopy of lesions is usually strongly positive

• Wood's light (ultraviolet light filtered through special glass) can be used to show Microsporum infections of hair, as they produce a green-blue fluorescence

Further reading

Midgley G, Clayton Y, Hay RJ. Medical mycology. London and

St Louis: Mosby-Wolfe, 1997 Elewski BE. Cutaneous fungal infections. New York: lgaku-Shoin, 1992 Evans EG, Richardson MD. Medical mycology: A practical approach. Oxford: Oxford University Press, 1989

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