Topical antifungals are products that treat fungal infections and which are applied directly to the skin, nails, or hair; vaginally; or inside the mouth. They are available as creams, gels, lotions, nail lacquers, ointments, powders, shampoos, sprays, and tinctures.
Fungal infections are caused by dermatophytes, yeasts, or molds.
There are about 40 different species of dermatophyte, and they obtain their nutrients from keratinized material, so typically are the organisms responsible for fungal infections of the skin, scalp or nails.
Yeasts are normal inhabitants of our skin but sometimes they grow unheeded which can result in symptomatic infections. Molds are an uncommon cause of fungal infections but they can cause tinea nigra (painless brown or black patches on the skin) or hard-to-treat nail infections.
Most antifungal agents treat both dermatophyte and yeast infections; however, some, such as nystatin, are not suitable for dermatophyte fungal infections.
What are topical antifungals used for?
Topical antifungals may be used to treat fungal infections of the skin, scalp, mucous membranes, nails, and vagina. Examples of infections that topical antifungals may treat include:
Other fungal infections not listed here may also be treated with topical antifungals.
What are the differences between topical antifungals?
Antifungal agents may be classified into a number of different types, depending on their structure and the way that they work. Many topical antifungals work by inhibiting production of ergosterol, a fundamental component of the fungal cell membrane and wall.
Note that only the antifungals that are available topically are listed here.
Azole antifungals
Azole antifungals are further classified into imidazoles and triazoles. Although all azoles work in the same way (by inhibiting an enzyme that converts lanosterol into ergosterol), there are differences in the spectrum of activity between imidazoles and triazoles.
Azole antifungals are metabolized through cytochrome p450 liver enzymes and are particularly susceptible to clinically-significant drug interactions with other medications metabolized through the same pathway, although this tends to only apply to topical products used inside the mouth, such as miconazole oral gel.
Polyene antifungals
Polyenes work by binding to ergosterol, disrupting the integrity of the fungal cell membrane. Nystatin is the only polyene antifungal available topically. Note that nystatin is not effective against dermatophyte infections but can be used to treat Candida infections.
Allylamine antifungals
Allylamines work in a similar way to azoles but have their effect earlier on in the ergosterol synthesis pathway. They inhibit the enzyme squalene epoxidase which converts squalene into ergosterol, disrupting synthesis of the fungal cell wall.
Terbinafine is also metabolized by cytochrome p450 liver enzymes and is particularly susceptible to clinically-significant drug interactions with other medications metabolized through this pathway, although this tends not to apply to topical products.
Other antifungals
Several other topical antifungals are available. Their mechanism of action differs to the antifungals listed above.
Are topical antifungals safe?
Topical antifungals are considered safe when used exactly as directed according to the product label. However, certain topical antifungals have been associated with serious side effects, for example:
- Miconazole oral gel: Should not be used in infants with an impaired swallowing reflex or in preterm infants in their first six months of life, or in babies less than four months old, because of the potential for airway obstruction
- Miconazole oral gel: May also cause clinically significant interactions with medicines (such as warfarin) metabolized through the same liver pathway because miconazole oral gel is absorbed through the mouth.
For a complete list of severe side effects, please refer to the individual drug monographs.
What are the side effects of topical antifungals?
Not everybody will experience side effects from topical antifungals. Some of the more commonly reported side effects include:
- Burning or stinging
- Rash
- Sensitivity reactions
- Skin irritation (redness, peeling, swelling).
Some vaginal topical antifungal preparations have been associated with burning, cramping, itching, pain, and bleeding.
For a complete list of side effects, please refer to the individual drug monographs.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
