Fungal Infections

Fungal (FUNG-gul) infections are caused by fungi (FUNG-eye) that can grow on the skin, nails, and hair and within internal organs.

What Are Fungal Infections?

Fungal infections are caused by fungi, tiny microbes ^* found in soil, air, and water, as well as on plants, animals, and people. There are at least 100,000 species of fungi. The most familiar types are the mushrooms that some people like to eat on pizza, the fuzzy white or blue-green mold that grows on forgotten foods in the back of the refrigerator, and the mildew on the shower curtain. Fungi grow best in warm, moist areas, like a steamy bathroom or the spaces between the toes.

Relatively few species of fungi cause fungal infections, also called mycoses (my-KO-seez). Those that produce infection can cause two basic types: superficial and systemic infections. Superficial infections are found on the skin, nails, or hair and usually are not serious. Systemic infections take hold inside the body, in individual organs or throughout the body, and can be severe. Systemic infections are more likely to appear in people who have weak immune systems, such as those who have cancer or AIDS ^* . In these people, the infections can cause chronic ^* disease and, in some cases, death.

What Are the Common Signs and Symptoms
of Fungal Infections?

Superficial fungal infections, such as jock itch, vaginal yeast infection, athlete's foot, and ringworm, typically are annoying but not very serious. Their symptoms generally include itchy, dry, red, scaly, or irritated skin. Systemic fungal infections often begin in the lungs and take time to develop. Severe infections occur in people whose immune systems have been weakened, allowing the infection to spread beyond the lungs to other organs. Symptoms of systemic fungal infections depend on which organs become infected and may include respiratory problems, extreme tiredness, coughing, weight loss, fever, night sweats, and headache.

What Are Some Specific Fungal Infections?

Tinea (TIH-nee-uh) is a general term given to a group of superficial fungal infections that affect the nails, feet (athlete's foot), groin area (jock itch), scalp, or skin (ringworm). Trichophyton and Microsporum fungi cause these related infections. Ringworm is identified by a red, scaly patch on the skin that looks like an expanding ring around a clearing center. Symptoms of athlete's foot include redness and cracking of the skin between the toes, and infected nails on the hands or feet usually look white and appear to be crumbling.

Candidiasis (kan-dih-DYE-uh-sis) is a superficial fungal infection caused by various strains of Candida (CAN-dih-duh) fungi. Candida is a yeastlike fungus often found in the mouth and the lining of the intestinal tract of healthy people. In people with weak immune systems, however, it can grow out of control, leading to an infection. A Candida infection of the mouth and throat is known as oropharyngeal (or-oh-fair-in-JEE-ul) candidiasis (OPC) or thrush, and infection of the vagina is known as vulvovaginal (vul-vo-VAH-jih-nul) candidiasis (VVC) or vaginal yeast infection. OPC can affect newborns, people with AIDS or diabetes ^* , and other people with weak immune systems. Its symptoms include white, thick patches on the tongue, mouth, and throat. Candida infection commonly occurs in newborns in the form of thrush or diaper rash. VVC is associated with vaginal burning or itching and a thick, cheeselike discharge. In certain situations, Candida can enter the bloodstream and spread to internal organs. This is seen most frequently in hospitalized patients who have weak immune systems and have received antibiotics.

A yeast colony, as seen with an electron microscope, looks like growing vegetation.

Custom Medical Stock Photo, Inc.

Aspergillosis (as-per-jih-LO-sis) is the name for a variety of systemic infections caused by Aspergillus (as-per-JIH-lus) fungi. If it is inhaled through the mouth or nose, the fungus can cause a mild allergic reaction or a more serious infection of the sinuses ^* and lungs. Symptoms of aspergillosis vary and may include fever, cough, chest pain, and wheezing. In severe cases, typically seen in people with weak immune systems, the infection can spread to other organs, including the brain, skin, and bones.

Blastomycosis (blas-toh-my-KO-sis) is a systemic infection caused by the Blastomyces dermatitidis fungus commonly found in soil in the southeastern, midwestern, and south-central United States. The disease's symptoms resemble those of the flu: joint and muscle pain, a cough that brings up sputum ^* , fever, chills, and chest pain. If it progresses, it can lead to chronic pulmonary ^* infection, causing permanent lung damage, or widespread disease that affects the bones, skin, and genital and urinary tracts. Blastomycosis leads to death in about 5 percent of patients.

Cryptococcosis (krip-toh-kah-KO-sis) is a systemic infection caused by the fungus Cryptococcus neofornans, usually found in soil or bird droppings. Typically, the fungus enters the body through the mouth or nostrils when someone inhales fungi spores ^* , and symptoms of a lung infection, such as cough and chest pain, may develop. Although infection with Cryptococcus usually produces no symptoms or only mild symptoms in healthy people, the infection may spread in people who have weak immune systems. If it spreads to the central nervous system, it can cause inflammation of the membranes covering the brain and spinal cord. This is especially common among people with AIDS.

Histoplasmosis (his-toh-plaz-MO-sis) is usually a mild systemic infection caused by Histoplasma capsulatum. This fungus is found in the eastern and central United States in soil that contains bird and bat feces ^* . When the soil is disturbed, the fungal spores may be inhaled. Histoplasmosis can cause flulike symptoms, including body aches, fever, and cough. Most people who become infected do not experience symptoms, but as with other fungal infections, people with weak immune systems are at risk for severe disease. In those cases, the infection affects the lungs and may spread to the liver ^* , spleen ^* , bones, and brain.

Sporotrichosis (spo-ro-trih-KO-sis) is a skin infection caused by the Sporothrix schenckii fungus, which is found in soil, thorny plants, hay, sphagnum (SFAG-num) moss, and other plant materials. It enters the skin through a small cut or puncture, such as a thorn might make. Soon, small reddish bumps resembling boils ^* form around the cut and often ulcerate ^* . In some cases, infection can spread to other parts of the body, such as the lungs or joints.

Coccidioidomycosis (kok-sih-dee-oyd-o-my-KO-sis) is a systemic infection caused by Coccidioides immitis, a fungus found in soil in the southwestern United States, Mexico, and South America. Most people with coccidioidomycosis have no symptoms, but 40 percent of patients experience a flulike illness, with fever, rash, muscle aches, and cough. Also know as valley fever, the infection can cause pneumonia ^* or widespread disease affecting the skin, bones, and membranes covering the brain and spinal cord.

How Common Are Fungal Infections?

Superficial fungal infections, such as athlete's foot and candidiasis, are fairly common. Systemic infections, on the other hand, are rare, appearing in less than one to two people of every 100,000 in the United States, according to the U.S. Centers for Disease Control and Prevention. They are more common in certain populations, such as people with AIDS or those who have had organ transplants.

With the so-called endemic ^* mycoses, rates of disease are higher in specific geographic areas. For example, coccidioidomycosis occurs in about 15 of every 100,000 people in parts of the southwestern United States (with 10 to 50 percent of the population testing positive for exposure to the fungus). In areas where histoplasmosis is found, up to 80 percent of the population test positive for exposure to Histoplasma capsulatum, but the disease develops only in people with weak immune systems.

Are They Contagious?

Some fungal infections, such as candidiasis and ringworm, can spread from person to person through contact with the infected area. Most infections, however, develop from fungi found naturally on the human body or in the environment. Many fungi that cause systemic respiratory disease are found in soil or in the droppings of animals or birds. Usually they are inhaled after the soil or droppings are disturbed, sending dust and fungal spores into the air.

How Do Doctors Make the Diagnosis?

Most superficial fungal infections are diagnosed based on their appearance and location. A doctor also may take a skin scraping to examine under the microscope or to culture ^* in a laboratory. Some fungi glow with a particular color under ultraviolet light, so a doctor may make the diagnosis by shining such a light on the affected area. Systemic infections can be diagnosed by collecting a sample of blood, urine, cerebrospinal fluid ^* , or sputum to culture.

Can Fungal Infections Be Treated?

Most superficial fungal infections are treated at home with antifungal creams or shampoos for 1 to 2 weeks. Oral (taken by mouth) antifungal medication also may be prescribed, if necessary. Some cases of fungal infection last for a while and may need to be treated with medicine for 2 to 4 weeks or even longer. Systemic illnesses often require hospitalization so that the patient can receive intravenous ^* antifungal drugs and supportive care.

Can Fungal Infections Be Prevented?

Preventing fungal infections can be difficult, because fungi are everywhere. In general, people who are otherwise healthy rarely contract systemic fungal infections. Practicing good hygiene, keeping the skin dry, and changing socks and underwear every day can help prevent superficial skin infections.