Fungal Infections

Fighting Fungus

As noted earlier in this section, the strength or weakness of the body's immune system is one of the most important factors in whether a fungus will cause disease and how severe that disease will be. A person with a healthy immune system is much less likely to get a systemic fungal infection than someone whose immune system is compromised due to disease or ongoing medical treatment.

The primary barriers we have against fungal infections are the same as those for other infections: intact skin, naturally occurring chemicals produced by our body, competition with normal bacteria that live in and on us, and the turnover rate of our skin cells. Our body even produces its own antifungalsubstance, which is secreted by our mucous membranes.

In most cases, fungi only cause disease if people have an underlying immune system problem. Most fungi that do cause disease live with us, like Candida, or around us, like Aspergillis and Cryptococcus. Minimizing exposure to fungi is important for hospitalized patients, but it is difficult to avoid these ubiquitous organisms.

Antigen Alert

Women who take systemic antibiotics for treating bacterial infections are more likely to experience opportunistic yeast infections.

First You Gotta Find It

It's not always easy for doctors to determine if a patient has a fungal infection. Physicians can grow cultures from a patient's skin scrapings or mucosal discharge from the throat or nose. X-rays and CT-scans can be helpful, and doctors sometimes identify fungi by examining tissue samples under a microscope.

Getting Rid of Fungi

Antigen Alert

Numerous topical antifungal drugs are available to treat vaginal yeast infections, and the availability of over-the-counter products for self-treatment has made the process easier. However, there is some concern that frequent use of these products (more than twice a year) may contribute to the emergence of drug-resistant Candida that can jeopardize a woman's health. Preliminary studies show only a low level of resistance, but the jury is still out and caution is recommended when using these products. It's still best to see your doctor to get a proper diagnosis and appropriate treatment.

Once a person has been diagnosed with a fungal infection, it can usually be treated with an antifungal drug or cream. Some are even available over the counter, such as treatments for vaginal yeast infections, but they should be used carefully and in consultation with a doctor to ensure they are the right treatment.

Antifungal drugs work by inhibiting the growth of a particular chemical in the cell membrane of fungi. Because this chemical is different from chemicals in the human cell wall, the antifungal drugs attack only the invading fungi, leaving the body's own cells intact. Other drugs used against fungi inhibit DNA and RNA replication, preventing the cells from multiplying.

The most widely-used antifungal drug, amphotericin B, is considered the gold standard because it is able to kill many different types of fungi. In the United States, this drug is only available intravenously.

Another class of drugs, called azoles, prevent new cell growth, but don't kill fungal cells that are already there. Most of the azoles can be used topically and are common ingredients in Mycelex and Monistat, used to treat yeast infections.

book cover

Excerpted from The Complete Idiot's Guide to Dangerous Diseases and Epidemics © 2002 by David Perlin, Ph.D., and Ann Cohen. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.