Conditions
a) Tinea pedis (Athlete's Foot)
Features: Infection usually starts in the toe webs, especially in the fourth web space (next to the little toe), where the tissue can become macerated, white and cracked. Infection can spread to the soles, heels and borders of the foot. Painful itching is common. The skin may fissure and allow entry of bacterial infection. The sole may be affected. With persistent infection the toenails may become involved, becoming dull, opaque and yellow in appearance. Over time the nail hardens and then starts to crumble.

Treatments: As for tinea corporis, plus: Imidazoles €“ additional compounds licensed for tinea pedis are bifonazole and ketoconazole. Griseofulvin €“ exclusively active against dermatophytes, through inhibition of cellular mitosis. It also binds to host cell keratin and reduces its degradation by fungal keratinases. It may also interfere with dermatophyte DNA production. It is available as a 1% topical spray. One spray is applied daily, increasing to three sprays daily for more severe or extensive infections affecting the sides or soles of the feet. Treatment should be continued for 10 days after lesions have disappeared. The treatment period should not exceed 4 weeks.

Tolnaftate €“ believed to act by distorting fungal hyphae and stunting mycelial growth. It is active against all species responsible for athlete's foot but has no antibacterial activity. It should be used twice daily and treatment should be continued for up to 6 weeks.

Undecenylates €“ undecenylic acid and zinc undecenylate are used in proprietary athlete's foot preparations. Zinc undecenylate has astringent properties, which helps to reduce the irritation and inflammation caused by the infection. Undecenylic acid, the active antifungal entity, is liberated from the zinc salt on contact with moisture on the skin. Up to four weeks' treatment may be needed to produce therapeutic results.

Benzoic acid €“ has antifungal activity, lowering the intracellular pH of infecting organisms. It is combined with salicylic acid in an emulsifying ointment base in Benzoic Acid Ointment Compound BP (Whitfield's Ointment). Benzoic acid may cause irritation of the skin, and should not come into contact with the eyes or mucous membranes. (Whitfield's Ointment can also be used for ringworm infections, but is less cosmetically acceptable than proprietary preparations.)

Additional advice: Wash and thoroughly dry feet and toes daily, particularly between the toes. Do not share towels in communal changing rooms. Wash towels frequently. Change socks daily. Wear flip-flops or plastic sandals in communal changing rooms and showers. When at home leave shoes and socks off as much as possible.

b) Tinea cruris (Dhobie Itch, Jock Itch)
Features: A fungal infection of the groin, occurring almost exclusively in young men. There is a brownish-red itchy rash, with a well-defined border, in the groin. Infection often spreads to involve the lower abdomen, scrotum and buttocks.
Treatment: As for tinea corporis. Additional advice: To prevent reinfection, wash and thoroughly dry the groin area daily; change underwear daily; do not share towels with others.

c) Onychomycosis (tinea unguium)
Features: The main form of fungal nail infection is distal and lateral subungual onychomycosis (DLSO). It is 20€“30 times more common on toenails than fingernails. The nail is thickened and has turned yellow or white. Changes usually start at the top of the nail but may spread across to the sides and down towards the nail base. Debris created as a result of the infection accumulates under the nail. There is scaling and distortion of the nail. The nail may become brittle and some or all of it may break off.

Treatment: Amorolfine 5% nail lacquer is licensed for pharmacy sale for the treatment of mild cases of DLSO, affecting up to two nails, in patients aged 18 years or over. Amorolfine is a morpholine derivative; its fungicidal action is based on ergosterol depletion and the accumulation of ignosterol in fungal cytoplasmic membrane, which causes the fungal cell wall to thicken and chitin to be deposited. The nail lacquer formulation builds a non-water-soluble film on the nail plate that remains at the application site for a week, acting as a depot for the drug. The product must be used weekly for up to 9 months, until all the infected nail has grown out and been replaced by healthy nail tissue.

Additional advice: A cure cannot be achieved overnight; it is important that treatment is continued and directions are followed. Wash and thoroughly dry feet every day. To prevent infection spreading to other toes, avoid tight-fitting or occlusive shoes. Rest shoes periodically to limit exposure to infectious fungi. Use antifungal powders once a week to help keep shoes free from pathogens. Exercise good nail care and be alert for infection recurrence. Visit a podiatrist regularly. Infection can be passed to others through contamination of shared facilities, so do not go barefoot in the family bathroom or public places.