Fungal Infection (Mycosis): Types, Causes & Treatments (2024)

What are fungal infections?

Fungal infections, or mycosis, are diseases caused by a fungus (yeast or mold). Fungal infections are most common on your skin or nails, but fungi (plural of fungus) can also cause infections in your mouth, throat, lungs, urinary tract and many other parts of your body.

What are fungi?

Fungi are living things that are classified separately from plants or animals. They move around by spreading out or sending spores (reproductive parts) into the air or environment. Many fungi live naturally in our body (mouth, GI tract, skin) but can overgrow under certain circ*mstances.

Scientists estimate that there are millions of fungi in the world, but only a small number of them are known to cause disease in people. This includes certain yeasts and molds.

What does a fungal infection look like?

Fungal infections on or in your skin can look red, swollen or bumpy. They can look like a rash or you might be able to see a lump under your skin. Fungal infections in your nails can make them discolored (yellow, brown or white), thick or cracked. Fungal infections in your mouth or throat can cause a white coating or patches.

Who is most at risk for fungal infections?

Anyone can get a fungal infection, especially ones that affect your skin or nails. Fungal infections are more common in places on your body that trap moisture or have a lot of friction. You’re at higher risk for infection, especially severe ones, if you have poor circulation or diabetes, or if you have a weakened immune system from:

• HIV/AIDS.
• Cancer or cancer treatments.
• Immunosuppressant medications (for autoimmune conditions or organ, stem cell or bone marrow transplants).

Is a fungal infection serious?

The most common fungal infections, like those on your skin or nails, aren’t usually serious. If you have a weakened immune system, you’re at higher risk of serious illness from certain fungal infections.

What are the types of fungal infections?

Fungal infections can be on the surface of your skin, nails or mucous membranes (superficial or mucocutaneous), underneath your skin (subcutaneous) or inside other organs of your body — like your lungs, brain or heart (deep infection).

Superficial fungal Infections

Superficial fungal infections affect your nails, skin and mucous membranes (like your mouth, throat or vagin*). Examples of superficial fungal infections include:

• Ringworm (dermatophytosis). A group of fungi that live off of skin, hair and nail cells (dermatophytes) cause ringworm. They can infect your feet (tinea pedis/athlete’s foot), your groin and inner thighs (tinea cruris/jock itch), your scalp (tinea capitis), your hands (tinea manuum), your facial hair and skin around it (tinea barbae) and other parts of your body (tinea corporis).
• Onychomycosis. Many types of fungi cause infections of your fingernails or toenails (onychomycosis). This can cause discolored and cracked nails.
• Candidiasis. Candida (usually Candida albicans) causes skin and mucous membrane (mucocutaneous) infections called candidiasis. These include oral thrush, some types of diaper rash, vagin*l yeast infections (vulvovaginitis), esophageal candidiasis and candidal intertrigo.
• Tinea versicolor/pityriasis versicolor. The fungus Malassezia causes skin discoloration called tinea versicolor or pityriasis versicolor.

Subcutaneous fungal infections

You can get a fungal infection under the surface of your skin (subcutaneous) if fungus gets into a cut or wound, usually through injury while working with plants (like a scratch from a thorn). They cause rashes, ulcers and other symptoms on your skin.

Subcutaneous fungal infections are more common in tropical and subtropical areas of the world. Examples include:

• Sporotrichosis (rose gardener’s disease). Sporothrix fungus causes sporotrichosis. You can also get sporotrichosis in your lungs or other parts of your body.
• Chromoblastomycosis. Many different fungi can cause chromoblastomycosis. It can cause a long-lasting (chronic) skin infections. Rarely, it spreads to other parts of your body.
• Eumycetoma. Many different fungi can cause eumycetoma. It most commonly affects your feet.

Deep fungal infections

Deep fungal infections are found in places in your body other than your skin, like your lungs, blood, urinary tract or brain. Some are opportunistic infections, meaning that they usually only cause disease in people with weakened immune systems.

Deep or invasive fungal infections include:

• Histoplasmosis. Histoplasma, the fungus that causes histoplasmosis, can infect your lungs, brain or other parts of your body. It’s commonly found in the Ohio and Mississippi River valleys.
• Coccidioidomycosis (Valley fever). Caused by the fungus Coccidioides, coccidioidomycosis can infect your lungs and, rarely, move to other parts of your body. It’s most common in California and Arizona.
• Blastomycosis. Blastomyces, the fungus that causes blastomycosis, commonly infects your bones, skin and lungs. Rarely, it can also infect your brain and spinal cord.
• Aspergillosis. Aspergillus, the mold that causes aspergillosis, can cause several types of lung infections, including allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis. It can also infect other parts of your body or form a fungus ball (aspergilloma).
• Candidal urinary tract infection. Bacteria cause most urinary tract infections (UTIs), but some are caused by yeast such as Candida.
• Invasive candidiasis. Various Candida species cause invasive candidiasis. It can infect your heart, blood (candidemia), brain, eyes (endophthalmitis), bones or other parts of your body.
• Pneumocystis pneumonia (PJP). The fungus Pneumocystis jirovecii can infect your lungs and cause Pneumocystis jirovecii pneumonia (PJP).
• Mucormycosis. A group of molds called mucormycetes cause mucormycosis. Mucormycetes can infect your sinuses and brain (rhinocerebral mucormycosis), lungs (pulmonary mucormycosis), intestines (gastrointestinal mucormycosis), skin (cutaneous mucormycosis) or many parts of your body at the same time (disseminated mucormycosis).
• Cryptococcosis. Cryptococcus neoformans and Cryptococcus gattii cause cryptococcosis. They usually infect your lungs, but sometimes can infect your brain and spinal cord (cryptococcal meningitis).