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What are fungal infections?
Fungal infections of the skin, nail, mouth and vagina
Many types of fungus germs (fungi) live harmlessly in the soil, on food, on our skin, and in other places in the environment. However, some types of fungi can thrive and multiply on the surface of the body to cause infection of the skin, nails, mouth or vagina.
The most common fungi to cause skin infections are the tinea group of fungi. For example, tinea pedis ('athletes foot') is a common fungal infection of the toes and feet.
A common infection of the mouth and vagina is called thrush. This is caused by an overgrowth of candida. Candida is a yeast which is a type of fungus. Small numbers of candida commonly live on the skin. But, certain conditions can cause candida to multiply and cause infection.
There are separate leaflets that give details of these common fungal infections.
Fungal infections within the body
Fungal infections of the skin, nails, vagina and mouth are quite common, but are rarely serious and dont usually spread deeper into the body. If you are otherwise healthy and have a normal immune system, it is rare for fungi to affect internal organs. However, fungal infections of the heart, lung, brain, and other organs sometimes do occur. These internal fungal infections can be serious, sometimes life-threatening.
Various types of fungi can cause internal infections. For example:
- Aspergillosis most commonly affects the lungs, but sometimes infects other organs.
- Cryptococcosis is uncommon, but can cause meningitis.
- Histoplasmosisis is rare, but can cause serious infections of the lung and other organs.
You are more at risk of developing an internal fungal infection if your immune system does not work properly. For example, if you are taking chemotherapy, if you have HIV/AIDS, etc. Some people with a poor immune system are prescribed regular antifungal medication to prevent serious fungal infections from developing.
What are antifungal medicines and how do they work?
There are several types of antifungal medicines. They come as creams, medicines to take by mouth, shampoos, and injections. Most work by damaging the cell wall of the fungus which causes the fungus cell to die.
Antifungal creams ('topical antifungals')
These are used to treat fungal infections of the skin and vagina. They include: clotrimazole, econazole, fenticonazole, miconazole, sulconazole, and tioconazole. They come in various different brand names.
Sometimes an antifungal cream is combined with other creams when two actions are required. For example, an antifungal cream is often combined with a mild steroid cream such as hydrocortisone to treat certain rashes. The antifungal clears the infection, and the mild steroid reduces the inflammation caused by the infection.
Antifungal medicines taken by mouth
There are various types. For example:
- Amphotericin and nystatin come as liquids and lozenges. Neither of these medicines are absorbed through the gut into the body. They are used to treat candida infections (thrush) of the mouth and throat.
- Terbinafine, itraconazole, fluconazole, ketoconazole, and griselfulvin come as tablets which are absorbed into the body. They are used to treat various fungal infections. The one chosen depends on what type of infection you have. For example:
- Terbinafine is commonly used to treat nail infections which are usually caused by a tinea type of fungus.
- Fluconazole is commonly used to treat vaginal thrush as an alternative to using antifungal cream. It is also used to treat and prevent certain fungal infections within the body.
A shampoo which contains ketoconazole is sometimes used to treat fungal infections of the scalp.
These may be used if you have a serious fungal infection within the body. Amphotericin, flucytosine, itraconazole, voriconazole and caspofungin are antifungal medicines that are sometimes used in this way. The one chosen depends on the type of fungus causing the infection.
Antifungal medicines are different to antibiotics (antibacterial medicines). Antibiotics do not kill fungi. In fact, you are more prone to getting a fungal infection if you take antibiotics. For example, many women develop thrush after taking a course of antibiotics. This is because the antibiotic may kill the normal harmless bacteria that live on your skin or vagina and make it easier for fungi to flourish.
What are the possible side-effects?
You should read the information leaflet that comes with your particular brand for a full list of possible side-effects. As a general rule:
- Antifungal creams and shampoos. These usually cause no side-effects and are easy to use. Occasionally, some women develop irritation around the vagina after applying vaginal antifungal products.
- Antifungal medicines by mouth. The most widely used are terbinafine for nail infections, amphotericin and nystatin for oral thrush, and fluconazole for vaginal thrush. These usually cause no side-effects. You can even buy fluconazole at pharmacies without a prescription as it is considered a medicine which is unlikely to cause problems. Some antifungal preparations cause liver problems or other side-effects in a small number of people.
- Antifungal injections. These have more risk of causing side-effects, sometimes serious problems. However, these are used to treat serious fungal infections and the risk of side-effects needs to be balanced against the need for treatment
- Antiviral Medicines
Antiviral drugs are medicines that cure or control virus infections.
Exclusive of the antiretroviral agents used in HIV (AIDS) therapy, there are currently only 11 antiviral drugs available, covering four types of virus. Acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex) are effective against herpesvirus, including herpes zoster and herpes genitalis. They may also be of value in either conditions caused by herpes, such as chickenpox and shingles. These drugs are not curative, but may reduce the pain of a herpes outbreak and shorten the period of viral shedding.
Amantadine (Symmetrel), oseltamivir (Tamiflu), rimantidine (Flumadine), and zanamivir (Relenza) are useful in treatment of influenza virus. Amantadine, rimantadine, and oseltamivir may be administered throughout the flu season as preventatives for patients who cannot take influenza virus vaccine.
Cidofovir (Vistide), foscarnet (Foscavir), and ganciclovir (Cytovene) have been beneficial in treatment of cytomegalovirus in immunosupressed patients, primarily HIV-positive patients and transplant recipients. Ribavirin (Virazole) is used to treat respiratory syncytial virus. In combination with interferons, ribavirin has shown some efficacy against hepatitis C, and there have been anecdotal reports of utility against other types of viral infections.
As a class, the antivirals are not curative, and must be used either prophylactically or early in the development of an infection. Their mechanism of action is typically to inactivate the enzymes needed for viral replication. This will reduce the rate of viral growth, but will not inactive the virus already present. Antiviral therapy must normally be initiated within 48 hours of the onset of an infection to provide any benefit. Drugs used for influenza may be used throughout the influenza season in high risk patients, or within 48 hours of exposure to a known carrier. Antiherpetic agents should be used at the first signs of an outbreak. Anti-cytomegaloviral drugs must routinely be used as part of a program of secondary prophylaxis (maintenance therapy following an initial response) in order to prevent reinfection in immunocompromised patients.