Also Known As
Mycoses
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This article waslast modified on October 10, 2017.
What are Fungal Infections?

Fungal infections (also called mycoses) represent the invasion of tissues by one or more species of fungi. They range from superficial, localized skin conditions to deeper tissue infections to serious lung, blood (septicemia) or systemic diseases. Some fungi are opportunistic while others are pathogenic, causing disease whether the immune system is healthy or not.

Fungi are one of four major groups of microbes (bacteria, viruses, parasites, and fungi). They exist in nature in one of two forms: as unicellular yeasts or as branching filamentous molds (also may be spelled as "moulds"). There are more than 1.5 million species of fungi in the environment, but only 300 species are associated with human disease. Of these, only about 20 to 25 species are common causes of infection.

Most fungal infections occur because a person is exposed to a source of fungi such as spores on surfaces, in the air, soil, or in bird droppings. Usually, infections develop because there is a break or deficiency in the body's immune system defenses and/or the person provides the "right environment" for the fungi to grow. Anyone can have a fungal infection, but certain populations are at an increased risk of fungal infections and recurrence of infections. These include organ transplant recipients, people who have HIV/AIDS, those who are on chemotherapy or immune system suppressants, and those who have an underlying condition such as diabetes or lung disease.

Fungal infections often develop on the surface of the skin, especially within skin folds and other areas kept warm and moist by clothing and shoes. These infections typically remain confined to small areas, such as between the toes, but may spread over the skin and/or penetrate into deeper tissues. Fungal nail infections are quite common, as are infections involving mucous membranes, such as the mouth and genitals. The sinuses are prone to fungal infections in certain populations. If fungi are introduced via a break in the skin, infections can develop in deeper layers of the skin (subcutaneous tissue), muscles, connective tissue, and even bones. Infections that start in the lungs may spread to the blood and can be carried throughout the body.

Some superficial fungal infections may resolve on their own, but most serious infections require medical attention and may need to be treated for extended periods of time. Those that penetrate into the body typically increase in severity over time and, if left untreated, may cause permanent damage and in some cases may eventually cause death. A few fungal infections may be easily passed on to other people, while others typically are not contagious.

Fungal infections may be categorized by the part of the body that they affect; by how deeply they penetrate the skin, subcutaneous tissue, muscle, connective tissue, or bone; by the organism causing the infection; or by the form(s) that the fungi take. Some organisms may cause both superficial and systemic infections.

 

Accordion Title
About Fungal Infections
  • Superficial Fungal Infections (Skin, Nail, Hair, Mucous Membranes)

    Superficial fungal infections may be caused by both yeast and mold forms of fungi. Skin is normally populated with a mixture of microbes called normal flora. Most of the time, normal flora do not cause illness and do not stimulate the immune system. If there is a break in the skin or if the immune system becomes weakened, then any of the microbes present can cause a wound or skin infection. If there is a shift in the balance of the microbes, such as a decrease in bacteria and an increase in the growth of fungi (sometimes seen with the use of broad-spectrum antibiotics), then the person may experience a fungal infection associated with the imbalance.

    Yeast infections
    Candidiasis is a common yeast infection that is due primarily to the overgrowth of Candida albicans and other species of Candida, which are part of the normal flora. In the mouth, candidiasis causes redness and white patches and is called "thrush." In babies, candida infections can cause diaper rash. In women, they can cause genital itching and vaginal discharge that is referred to as a "yeast infection." According to the Centers for Disease Control and Prevention (CDC), almost 75% of women will have at least one yeast infection in their lifetime. Men can also get genital yeast infections, although this is rare. Candidiasis can cause a variety of other infections, including nail infections, and it can become systemic, especially in those who have a weakened immune system. (Read about Systemic Infections).

    Dermatophyte infections
    Athlete's foot, jock itch, and fungal nail infections are common infections that can be passed from person to person. These fungal infections can cause reddening, peeling, blistering, and scaling of the skin; itching, deformation and brittleness of affected nails; and brittle hair. They are caused by dermatophytes, a group of fungi that includes Trichophyton, Microsporum, and Epidermophyton species. Dermatophytes feed on keratin and rarely penetrate below the skin. Infections caused by these fungi are also commonly called ringworm (although they are not caused by a worm) and "tinea."

    • Athlete's foot (tinea pedis) is found between the toes and sometimes covers the bottom of the foot.
    • Jock itch (tinea cruris) may extend from the groin to the inner thigh.
    • Scalp and hair infection (tinea capitis) affects hair shaft, primarily in children.
    • Finger or toenail infection (tinea unguium) typically affects toenails but may also affect fingernails.
    • Ringworm of the body (tinea corporis) can be found anywhere on the body.
    • Barber's itch (tinea barbae) affects the bearded portion of the face.


    Others
    Tinea versicolor is associated with multicolored patches or lesions on the skin and is caused not by a dermatophyte, but by Malassezia furfur, a yeast. It is a condition that is common in young adults. Sporotrichosis is a condition caused by the fungus Sporothrix schenckii, which is not a dermatophyte. It is an infection of the skin and subcutaneous tissue that has been abraided by thorny plants, pine needles, and sphagnum moss where this fungus normally resides. Some fungi associated with systemic infections, such as Coccidioides immitis and Blastomyces dermatitidis, may also cause skin rashes or lesions.

  • Deep Tissue, Blood, Lung and Systemic Fungal Infections

    A variety of fungi can cause deep tissue and lung infections that have the potential to spread to the blood or the rest of the body (systemic). Some of these fungi are found throughout the U.S., while others are found in specific regions of the country. People frequently become infected when they come in contact with infected soil.

    Lung infections typically start with the inhalation of fungal spores. With lung infections, as with fungal infections that have spread below the surface of the skin, the invading fungi have the potential to spread from the original infection location and move to the blood (septicemia) and/or spread throughout the body to other organs, tissues, bone, and sometimes into the meninges that cover the spinal cord and into the brain, causing meningitis.

    In many people with competent immune systems, fungal lung infections may cause only mild to moderate flu-like symptoms such as coughing, fever, muscle aches, headaches, and rashes. In these people, the infection may remain localized the the lungs and not spread (the organisms are walled off in granulomas). However, people with localized infections may, at some point in their life, become immunocompromised and the silent, chronic fungal infection may then become an active, acute infection.

    Some lung infections caused by fungi may take months to years to cause symptoms, slowly and progressively growing worse and disseminating throughout the body, causing night sweats, chest pain, weight loss, and enlarged lymph nodes. Others may progress rapidly, causing pneumonia and/or septicemia.

    Fungal lung infections are more likely to be severe in people who have underlying lung disease and/or a weakened immune system, such as those with HIV/AIDS or cancer, organ or stem cell transplant patients, hospitalized patients, and those who take medications that weaken the immune system. Both acute and chronic fungal infections can cause permanent lung, organ, and bone damage and can be fatal.

    Some common fungal lung infections that have the potential to become systemic include:

    • Aspergillosis, caused by Aspergillus fumigatus or several other Aspergillus species. Tese fungi are commonly found in soil, plants, and house dust. They can cause fungal masses in the sinuses and lungs and, in some cases, can spread to the brain and bones.
    • Blastomycosis, caused by Blastomyces dermatitidis found in moist, organic-rich soil, particularly in woodland areas of the southeastern and south-central United States. Although most people who breathe in the spores don't get sick, some of those who do may develop flu-like symptoms. The infection can become severe in people with compromised immune systems, especially if it spreads from the lungs to other organs.
    • Coccidioidomycosis, also called Valley fever, caused primarily by Coccidioides immitis, which is found in the arid soil of the southwestern U.S., Mexico, and South America. Recently, the fungus was found in south-central Washington state. The term "Valley fever" usually refers to Coccidioides infection of the lungs, but the infection can spread to other parts of the body in severe cases (this is called "disseminated coccidioidomycosis").
    • Cryptococcosis, caused by Cryptococcus neoformans or, rarely, by another Cryptococcus species found in soil and are associated with bird droppings. Anyone may become infected, but the highest prevalence in the U.S. is in people who have HIV/AIDS. An emerging infection, Cryptococcus gatti, has been identified in the Pacific Northwest and is thought to pose a threat to individuals in that area. Cryptococcosis usually affects the lungs or the central nervous system, but it can also affect other parts of the body. Brain infections are called cryptococcal meningitis.
    • Histoplasmosis, caused by Histoplasma capsulatum found primarily in the east and central U.S. in soil that contains large amounts of bird and bat droppings. Those who become ill after breathing in Histoplasma spores may have a fever, cough, and fatigue. The infection can become severe in those with weakened immune systems, especially if it spreads from the lungs to other organs.
    • Candidiasis, caused by Candida species, which are part of the normal human flora, and are found worldwide. Infections occur in the moist mucous membranes but can occur in other parts of the body as well. Systemic—or invasive—candidiasis can affect the blood, heart, brain, eyes, bones, and other parts of the body. Candida bloodstream infection, which is the most common form of invasive candidiasis, is called candidemia. Candidemia is currently the fourth most common cause of hospital-acquired septicemia in the United States.
    • Pneumocystis pneumonia (PCP) is a serious lung infection caused by Pneumocystis jiroveci (formerly known as Pneumocystis carinii), which is found worldwide. PCP most commonly affects those with compromised immune systems, including those with HIV/AIDS, organ transplant recipients, and those undergoing treatment for cancer. Although people with HIV/AIDS are less likely to acquire PCP today than in years past, it is still a significant public health problem.
  • Tests

    Laboratory Tests
    Various laboratory tests may be used to help diagnose and guide treatment of fungal infections. For detailed information, see the article on Fungal Tests.

    Tests for superficial infections
    Many fungal skin infections are diagnosed by a healthcare practitioner based on a clinical evaluation and experience. In addition to general symptoms, many skin infections have characteristic signs, such as the appearance of infected nails, or typical locations on the body, such as the growth of athlete's foot between the toes. A clinical evaluation cannot, however, definitively tell the healthcare practitioner which microbe is causing a fungal infection. A few laboratory tests may be useful in detecting and confirming a fungal infection and may help guide treatment. They may include:


    Tests for deep tissue, lung, and systemic infections
    Symptoms of lung and systemic fungal infections are frequently nonspecific and may be confused with those due to other microbes or another disease process. Laboratory testing is primarily used to diagnose these serious fungal infections, to identify the microbe responsible, and to determine its likely susceptibility to specific antimicrobial agents. Sometimes testing is also performed to detect and identify bacteria that may be causing a concurrent infection. The sample collected depends upon the suspected location(s) of the infection. It may include the collection of blood, sputum, urine, cerebrospinal fluid (CSF), and/or the collection of a tissue biopsy. Testing may include:

    • Microscopic examination of the sample using techniques such as KOH prep and calcofluor white stain to determine whether or not the infection is due to a fungus.
    • Fungal culture – this is the primary test used to diagnose a fungal infection. Many fungi are slow-growing and may require up to several weeks for detection and identification.
    • Susceptibility testing – a follow-up test to the fungal culture that is sometimes ordered to help guide treatment.
    • Antigen and Antibody testing – available for a variety of different fungi but only for deep or systemic infections; may be performed on blood or other body fluids, such as CSF. Antibody testing typically involves measuring the level or titer of antibody.
    • Molecular testing may be used to detect the genetic material of the fungus causing the infection and may be performed on blood or other body fluids, or on a sample of the microbe grown in culture.

    Other tests that may be ordered in conjunction with fungal tests include:


    Non-laboratory Tests
    In some cases, imaging scans such as x-rays may be ordered to detect fungal masses, such as those that may develop in the sinuses or lungs, and to evaluate the extent of tissue damage.

  • Treatment

    Some fungal infections are caused by normal flora and by fungi that are present throughout the environment; therefore, not every fungal infection can be prevented and some of them may recur after treatment.

    Many superficial fungal infections will resolve with only a topical antifungal treatment, but some cases may require oral antifungal therapy. People with serious lung and systemic fungal infections will require oral and sometimes intravenous medications. The choice of which antifungals to use is based upon the healthcare practitioner's experience, on the results of the fungal culture, and on the results of susceptibility testing, if it is performed.

    Treatment length varies by the type, location, and persistence of infection. Vaginal yeast infections, for instance, may require only a few days of therapy to resolve, while fungal skin infections may take a couple of months. Systemic infections may require consistent treatment for a couple of years in order to resolve and, in some cases, people with suppressed immune systems may need to be treated with a maintenance therapy for the rest of their lives. Occasionally, surgery may be necessary to remove fungal masses.

View Sources

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used. To access online sources, copy and paste the URL into your browser.

Sources Used in Current Review

Centers for Disease Control and Prevention (December 2, 2014 updated). Types of Fungal Diseases. Available online at http://www.cdc.gov/fungal/diseases/index.html. Accessed August 27, 2016.

Blackwell M. The Fungi: 1, 2, 3 ... 5.1 Million Species? American Journal of Botany. 2011; 98(3): 426–438.

Centers for Disease Control and Prevention (June 12, 2015 updated.) Candidiasis. Available online at http://www.cdc.gov/fungal/diseases/candidiasis/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (February 13, 2014 updated.) Genital/Vulvovagial Candidiasis (VVC). Available online at http://www.cdc.gov/fungal/diseases/candidiasis/genital/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (June 12, 2015 updated). Invasive Candidiasis. Available online at http://www.cdc.gov/fungal/diseases/candidiasis/invasive/index.html. Accessed August 27, 2016.

Calandra Delaloye J, Thierry C. Invasive Candidiasis As a Cause of Sepsis in the Critically Ill Patient. Virulence. 2014; 5:1, 161–169.

Centers for Disease Control and Prevention (December 4, 2015 updated.) Ringworm. Available online at http://www.cdc.gov/fungal/diseases/ringworm/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (February 13, 2014 updated.) Sporotrichosis. Available online at http://www.cdc.gov/fungal/diseases/sporotrichosis/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (November 13, 2015 updated.) Aspergillosis. Available online at: http://www.cdc.gov/fungal/diseases/aspergillosis/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (December 28, 2015 updated.) Blastomycosis. Available online at http://www.cdc.gov/fungal/diseases/blastomycosis/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (June 29, 2015 updated). Valley Fever (Coccidioidomycosis). Available online at http://www.cdc.gov/fungal/diseases/coccidioidomycosis/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (November 28, 2015 updated). C. neoformans Infection. Available online at http://www.cdc.gov/fungal/diseases/cryptococcosis-neoformans/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (December 16, 2015 updated). C. gatti Infection. Available online at http://www.cdc.gov/fungal/diseases/cryptococcosis-gattii/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (November 21, 2015 updated.) Histoplasmosis. Available online at http://www.cdc.gov/fungal/diseases/histoplasmosis/index.html. Accessed August 27, 2016.

Centers for Disease Control and Prevention (February 13, 2014 updated.) Pneumocystis Pneumonia. Available online at http://www.cdc.gov/fungal/diseases/pneumocystis-pneumonia/index.html. Accessed August 27, 2-16.

Sources Used in Previous Reviews

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 1569, 1570, 1532, 1616.

Forbes, B. et. al. (© 2007). Bailey & Scott's Diagnostic Microbiology, Twelfth Edition: Mosby Elsevier Press, St. Louis, Missouri. Pp 629-716.

(2008 March 27, Modified). Candidiasis. CDC, Division of Foodborne, Bacterial, and Mycotic Diseases [On-line information]. Available online at http://www.cdc.gov/nczved/dfbmd/disease_listing/candidiasis_gi.html. Accessed on 8-14-08.

(2008 March 27, Modified). Aspergillosis (Aspergillus). CDC, Division of Foodborne, Bacterial, and Mycotic Diseases [On-line information]. Available online at http://www.cdc.gov/nczved/dfbmd/disease_listing/aspergillosis_gi.html. Accessed on 8-14-08.

(2008 March 27, Modified). Blastomycosis. CDC, Division of Foodborne, Bacterial, and Mycotic Diseases [On-line information]. Available online at http://www.cdc.gov/nczved/dfbmd/disease_listing/blastomycosis_gi.html. Accessed on 8-14-08.

(2008 March 27, Modified). Coccidioidomycosis. CDC, Division of Foodborne, Bacterial, and Mycotic Diseases [On-line information]. Available online at http://www.cdc.gov/nczved/dfbmd/disease_listing/coccidioidomycosis_gi.html. Accessed on 8-14-08.

(2008 March 27, Modified). Cryptococcus. CDC, Division of Foodborne, Bacterial, and Mycotic Diseases [On-line information]. Available online at http://www.cdc.gov/nczved/dfbmd/disease_listing/cryptococcus_gi.html. Accessed on 8-14-08.

(2008 March 27, Modified). Dermatophytes (Ringworm). CDC, Division of Foodborne, Bacterial, and Mycotic Diseases [On-line information]. Available online at http://www.cdc.gov/nczved/dfbmd/disease_listing/dermatophytes_gi.html. Accessed on 8-14-08.

(2008 March 27, Modified). Histoplasmosis. CDC, Division of Foodborne, Bacterial, and Mycotic Diseases [On-line information]. Available online at http://www.cdc.gov/nczved/dfbmd/disease_listing/histoplasmosis_gi.html. Accessed on 8-14-08.

(2008 March 27, Modified). Sporotrichosis. CDC, Division of Foodborne, Bacterial, and Mycotic Diseases [On-line information]. Available online at http://www.cdc.gov/nczved/dfbmd/disease_listing/sporotrichosis_gi.html. Accessed on 8-14-08.

Lehrer, M. (2006 October 26, Updated). Fungal nail infection. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/001330.htm. Accessed on 8-14-08.

Lehrer, M. (2006 October 16, Updated). Tinea Corporis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000877.htm. Accessed on 8-14-08.

Berman, K. (2007 April 12, Updated). Athlete's Foot. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000875.htm. Accessed on 8-14-08.

Lehrer, M. (2006 October 16, Updated). Tinea capitis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000878.htm. Accessed on 8-14-08.

Berman, K. (2007 April 12, Updated). Jock itch. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000876.htm. Accessed on 8-14-08.

Lehrer, M. (2007 April 12, Updated). Skin lesion KOH exam. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003761.htm. Accessed on 8-14-08.

Berman, K. (2006 October 13, Updated). Wood's lamp. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003386.htm. Accessed on 8-14-08.

Stokowski, L. (2007 November 20). Fungal Skin and Nail Infections: Practical Advice for Advanced Practice Clinicians. Medscape Nursing Perspectives [On-line information]. Available online at http://www.medscape.com/viewarticle/566002. Accessed on 8-16-08.

Pappas, P. (2007 May 31). Invasive Fungal Infections: Diagnosis, Treatment, and Prophylaxis CME/CE. Medscape [On-line information]. Available online at http://www.medscape.com/viewarticle/556373. Accessed on 8-13-08.

(2005 November, Revision). Fungi. The Merck Manual for Healthcare Professionals [On-line information]. Available online at http://www.merck.com/mmpe/sec14/ch180/ch180a.html?qt=fungal%20infection&alt=sh#sec14-ch180-ch180a-1521. Accessed on 8-13-08.

(2005 November, Revision). Fungal Skin Infections. The Merck Manual for Healthcare Professionals [On-line information]. Available online at http://www.merck.com/mmpe/sec10/ch120/ch120a.html. Accessed on 8-13-08.

(© 2006-2008). Yeast-Associated Syndromes. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/InfectiousDz/Fungi/Yeasts.html. Accessed on 8-16-08.

(© 2006-2008). Mold-Associated Syndromes. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/InfectiousDz/Fungi/Molds.html. Accessed on 8-16-08.

Ellis, D. (2008 February 7, Modified). Calcofluor White with 10% KOH. Mycology Online [On-line information]. Available online at http://www.mycology.adelaide.edu.au/Laboratory_Methods/Microscopy_Techniques_and_Stains/calcofluor.html. Accessed on 8-16-08.

(March 2011) Mandanas R. Fungal Pneumonia. Medscape Reference Article. Available online at http://emedicine.medscape.com/article/300341-overview. Accessed October 2012.

(May 21 2012) Hidalgo J. Candidiasis. Medscape Reference. Available online at http://emedicine.medscape.com/article/213853-overview. Accessed October 2012.

(Aug 26 2011) Fayyaz J. Histoplasmosis. Medscape Reference. Available online at http://emedicine.medscape.com/article/299054-overview. Accessed October 2012.

(Dec 8 2011) Hospinthal D. Coccidioidomycosis. Medscape Reference. Available online at http://emedicine.medscape.com/article/215978-overview. Accessed October 2012.

(October 1, 2012) King J. Cryptococcocus. Medscape Reference. Available online at http://emedicine.medscape.com/article/215354-overview. Accessed October 2012.

American Thoracic Society. Fungal Lung Disease. PDF available for download at http://www.thoracic.org/education/breathing-in-america/resources/chapter-9-fungal-lung-disease.pdf. Accessed October 2012.

(January 5, 2012) Centers for Disease Control and Prevention. Fungal Infections. Available online at http://www.cdc.gov/fungal/. Accessed October 2012.

(March 9, 2011) Rashid M. Tinea in Emergency Medicine. Medscape Reference. Available online at http://emedicine.medscape.com/article/787217-overview. Accessed October 2012.

(Feb 8 2011) Varky B. Blastomycosis. Medscape Reference. Available online at http://emedicine.medscape.com/article/296870-overview. Accessed October 2012.

(Updated August 29, 2011) Vyas J. Valley Fever. MedlinePlus Medical Encyclopedia. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/001322.htm. Accessed October 2012.

(Updated September 15, 2010) Dugdale D. Skin lesion of coccidioidomycosis. MedlinePlus Medical Encyclopedia. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000866.htm. Accessed October 2012.