A fungus is an organism that grows on and digests organic matter. Fungi can exist as single-celled microbes, such as yeasts; or they can exist as complex, multicellular organisms, such as moulds, mildews, or mushrooms.
Scientists have discovered many beneficial uses for fungi. Fungi are used for making various foods and drinks. They are also used for making antibiotics and other pharmaceutical drugs.
Unfortunately, there are a small number of fungi that can cause diseases in humans. Any disease caused by a fungus is referred to as a fungal disease. Another term used for fungal disease is fungal infection.
Many fungal diseases affect the respiratory system. The resulting symptoms include the following:
Fungi can also produce extrapulmonary symptoms. These are listed below:
Below is a list of fungal diseases and the fungi that cause them.
| Fungal Disease | Fungus |
| Ringworm | Trichophyton, Microsporum, and Epidermophyton moulds |
| Candidiasis | Candida yeasts |
| Blastomycosis | Blastomyces yeasts |
| Cryptococcosis | Cryptococcus neoformans and C. gattii yeasts |
| Paracoccidioidomycosis | Paracoccidioides brasiliensis and P. lutzii yeasts |
| Coccidioidomycosis (Valley Fever) | Coccidioides immitis and C. posadasii yeasts |
| Histoplasmosis | Histoplasma capsulatum yeast |
| Aspergillosis | Aspergillus moulds |
| Pneumocystis pneumonia (PCP) | Pneumocystis jirovecii yeast |
| Mucormycosis | Rhizopus, Rhizomucor, and Mucor fungi |
| Talaromycosis | Talaromyces marneffei yeast |
| Sporotrichosis | Sporothrix schenckii and S. brasiliensis yeasts |
The fungi that cause fungal diseases are transmitted through various means. Some fungi are contagious and can be spread from person to person through the air or through skin contact. They can also be spread by touching infected animals or contaminated surfaces. Examples include fungal nail infections, ringworm, and Pneumocystis pneumonia.
Some fungal diseases are not contagious. They are acquired by inhaling microscopic, fungal cells or spores from the air. Examples include blastomycosis, cryptococcosis, and Valley Fever.
For some fungal diseases, the causative fungi originate from within the human body. The fungi typically do not cause problems, but various factors (i.e., changes in the immune system) can lead the fungi to grow. This, in turn, causes fungal diseases to develop. Examples are vaginal candidiasis and oral candidiasis (also known as thrush).
It is uncommon to find a fungal disease in an otherwise healthy individual. Fungal diseases are opportunistic and tend to arise in individuals with weakened immune systems. Risk factors include the following:
Location is another important risk factor to consider. Many fungi that cause fungal diseases inhabit specific locations throughout the world. For example, the fungi that cause Valley Fever are found in southwestern United States and parts of Mexico and South America. Travel to these areas will increase one’s chances of developing Valley Fever.
A fungal disease is often diagnosed after a doctor performs the following:
Fungal diseases can also be diagnosed through various tests. Small samples of blood, urine, tissue (i.e., skin or nail scrapings), cerebral spinal fluid, or sputum can be studied under a microscope, tested with an antigen test, or used to grow a fungal culture. If a fungal infection has affected the lungs, a chest x-ray or CT scan proves useful for diagnosis.
Fungal diseases are treated with antifungal medication. There are numerous different antifungal medications available, including amphotericin B, azoles, echinocandins, and flucytosine. These medicines are available as creams, oral suspensions, tablets, or IV formulations. Depending on the type and severity of the fungal disease, the antifungal medication may need to be taken for as long as a year. In severe cases, fungal diseases may necessitate surgery to remove infected tissue.