What is a fungal skin infection?
Fungal skin infections are caused by:
- Dermatophytes, resulting in tinea corporis, tinea cruris, tinea faciei, tinea manuum, tinea pedis, tinea capitis and tinea barbae
- Yeasts, resulting in candida intertrigo and pityriasis versicolor
- Moulds, resulting in tinea nigra and nail plate infections.
What is a topical antifungal medication?
A topical antifungal medication is a cream, solution, lotion, powder, gel, spray or lacquer applied to the skin surface to treat a fungal infection.
Many antifungal medications are suitable for both dermatophyte and yeast infections. Others are more specific to one or the other type of fungus. Those unsuitable for dermatophyte fungal infections are marked with an asterisk (*) in the list that follows.
- Whitfield ointment (3% salicylic acid, 6% benzoic acid in petrolatum)
- Undecylenic alkanolamide
- Ciclopirox olamine
- Polyenes *
- Nystatin
- Imidazoles
- Bifonazole
- Clotrimazole
- Econazole
- Efinaconazole
- Ketoconazole
- Luliconazole
- Miconazole
- Sulconazole
- Tioconazole
- Allylamine
- Thiocarbamates
- Tolciclate
- Tolnaftate
- Benzoxaborole
- Tavaborole
How are topical antifungal agents used?
Topical antifungals can be obtained over the counter without a doctor's prescription. They are generally applied to the affected area twice daily for two to four weeks, including a margin of several centimetres of normal skin. Treatment should continue for one or two weeks after the last visible rash has cleared. They can often cure a localised infection, although recurrence is common so repeated treatment is often necessary.
Scalp antifungal agents
Antifungal shampoos are mainly used to treat dandruff / seborrhoeic dermatitis but are used as an adjunct for tinea capitis and scalp psoriasis.
The most effective ingredients are ketoconazole, miconazole and ciclopirox (Stieprox® liquid), but many other shampoos marketed for dandruff have antifungal properties.
Preparations for nail fold infections
There are many antiseptic and antifungal preparations to control nail fold infections (paronychia). They should be applied two or three times daily for several months.
- Clotrimazole solution
- Econazole solution
- Miconazole
- Sulfacetamide 15% in spirit
Preparations for nail plate infections
Distal onychomycosis can be treated with an antifungal lacquer applied once or twice weekly. The medication should be applied to the surface of the cleaned nail plate after it has been roughened using an emery board. Extra lacquer should be applied under the edge of the nail.
These can be expected to reduce and sometimes cure the infection, provided that:
- No more than 50% of the nail plate is infected
- The growing part of the nail plate (the matrix) is not involved
- There is no complicating internal disease (such as diabetes) or skin condition (such as psoriasis).
Available preparations are:
- Amorolfine
- Ciclopirox
- Bifonazole cream + urea ointment
- Efinaconazole solution
- Tavaborole solution.
Treatment needs to be undertaken for long periods (a year or longer) because nails take a long time to grow, especially in older individuals. Nail polish is not recommended, in case it interferes with the efficacy of the product, although this is not proven.
Preparations for oral infections
Oral candidiasis can be treated with:
- Nystatin *
- Amphotericin B *
- Miconazole.
Note: miconazole oral gel should not be used in patients who are taking warfarin because it has been reported to cause a dangerous interaction, which could result in serious bleeding.
Preparations for a vaginal infection
Vulvovaginal candidiasis can be treated with:
- Nystatin *
- Clotrimazole
- Econazole
- Isoconazole
- Miconazole
- Tioconazole.
* Unsuitable for dermatophyte fungal infections
Combination products
Topical antifungals may be sold with an oral antifungal medication, for example, fluconazole capsule in combination with clotrimazole cream.
Antifungal creams are sometimes combined with:
- Hydrocortisone or another topical steroid
- Antibacterial agent
- Both topical steroid and antibacterial agent.
A strong topical steroid can mask the fungal infection, and, as they are not curative, they can result in more extensive infection (tinea incognito) and adverse effects such as cutaneous atrophy.
When should an oral antifungal medication be used?
Oral antifungal medications may be required for a fungal infection if:
- It is extensive or severe
- It resists topical antifungal therapy
- It affects hair-bearing areas (tinea capitis and tinea barbae).
Antifungal drug resistance
In recent years, both topical and oral allylamine and triazole antifungal drug resistance has become a problem, particularly in the Indian subcontinent.
Extensive therapy-resistant dermatophyte infection should prompt this as a possible problem. Where available, fungal culture and estimation of drug minimum inhibitory concentration determined to guide appropriate medication
For more information, see antifungal drug resistance.