Fungal Infections
Infections caused by fungi, from skin to internal organs
Quick Facts
- Type: Infection caused by fungi
- Common sites: Skin, nails, mouth, vagina, lungs
- Common examples: Athlete's foot, ringworm, thrush, yeast infection
- Treatment: Antifungal creams, tablets, or other medicines
Overview
Fungal infections, also called mycoses, are caused by fungi such as molds, yeasts, and dermatophytes. Fungi are present everywhere in the environment and some normally live on the body without causing harm. An infection develops when fungi overgrow or invade tissue, often when conditions are warm and moist or when the body's defenses are weakened.
Most fungal infections are mild and affect the surface of the body, such as athlete's foot, ringworm, nail infections, and yeast infections of the mouth or vagina. Less commonly, fungi cause deeper infections of the lungs or, in people with seriously weakened immune systems, life-threatening infections that spread through the body. The right treatment depends on the type of fungus and where the infection is.
Symptoms
Symptoms depend on the location of the infection.
- Skin infections: Itchy, red, scaly, or ring-shaped rashes, peeling between the toes, or discolored patches.
- Nail infections: Thick, brittle, discolored, or crumbling nails.
- Oral thrush: White patches in the mouth, soreness, and difficulty swallowing.
- Vaginal yeast infection: Itching, burning, redness, and a thick white discharge.
- Scalp infection: Itchy, scaly patches with hair loss.
- Lung infections: Cough, fever, chest discomfort, and feeling unwell, which can resemble pneumonia.
Widespread or deep fungal infections can cause fever and serious illness and require urgent care, especially in people with weakened immune systems.
Causes
Different fungi cause different infections:
- Dermatophytes: Cause athlete's foot, jock itch, ringworm, and most nail and scalp infections.
- Yeasts (such as Candida): Cause oral thrush, vaginal yeast infections, and skin-fold infections.
- Environmental molds (such as Aspergillus) and other fungi: Can cause lung and deeper infections, usually after spores are inhaled.
Fungi thrive in warm, damp conditions, so sweat, tight clothing, communal showers, and prolonged moisture all increase the risk of skin and nail infections.
Risk Factors
- Excessive sweating and warm, humid environments
- Diabetes
- A weakened immune system from illness, chemotherapy, or immune-suppressing medicines
- Recent or repeated antibiotic use, which can allow yeast to overgrow
- Tight or damp clothing and shared changing-room floors
- Pregnancy and hormonal changes (for yeast infections)
- Older age and broken or damaged skin
Diagnosis
Many fungal infections are recognized by their appearance, but tests are used when the diagnosis is uncertain or the infection is deep.
- Skin or nail scraping (KOH test): A sample is examined under the microscope for fungal elements.
- Fungal culture: Identifies the specific fungus and guides treatment when needed.
- Swabs: Of the mouth or vagina to confirm yeast infections.
- Imaging and blood or tissue tests: For suspected lung or deep infections.
Treatment
Treatment depends on the type and severity of infection.
- Topical antifungals: Creams, sprays, powders, and shampoos for most skin and scalp infections.
- Antifungal nail treatments or tablets: Nail infections often need oral medication for weeks to months.
- Vaginal or oral antifungals: For yeast infections and thrush.
- Oral or intravenous antifungal medication: For widespread, deep, or lung infections, given under medical supervision.
- Keeping the area clean and dry: An important part of clearing and preventing skin infections.
Prevention and Self-Care
- Keep skin clean and dry, especially between the toes and in skin folds
- Wear breathable clothing and change out of damp or sweaty clothes
- Wear sandals in communal showers and changing rooms
- Do not share towels, shoes, or nail tools
- Manage diabetes and treat athlete's foot promptly to prevent spread
- Use antifungal powder if you are prone to recurrent infections
When to See a Doctor
See a doctor if a suspected fungal rash does not improve with over-the-counter treatment, if nail or scalp infections develop, or if infections keep coming back. Seek urgent care for fever, cough, and feeling very unwell that might suggest a lung or bloodstream infection, particularly if your immune system is weakened by illness or medication. People with diabetes or a compromised immune system should consult a doctor early, since fungal infections can become more serious for them.
Frequently Asked Questions
Are fungal infections contagious?
Many skin and nail fungal infections can spread through direct contact or shared items such as towels, shoes, and changing-room floors. Yeast and deep fungal infections are generally not spread person to person in the same way. Good hygiene and not sharing personal items reduce the risk.
Why do fungal infections keep coming back?
Recurrence often happens because the warm, moist conditions that favor fungi persist, because treatment was stopped too soon, or because of an untreated source such as athlete's foot. Underlying factors like diabetes or a weakened immune system can also make infections recur.
Can fungal infections be serious?
Most are mild and limited to the skin, nails, or mucous membranes. However, fungi can cause serious lung or bloodstream infections, particularly in people with weakened immune systems, so persistent fever and feeling very unwell warrant prompt medical care.
How long do fungal infections take to clear?
Skin infections often improve within a couple of weeks of antifungal treatment, but nail infections can take several months because the nail grows slowly. Completing the full course of treatment is important to prevent the infection returning.
Can I treat a fungal infection at home?
Many mild skin infections respond to over-the-counter antifungal creams along with keeping the area clean and dry. See a doctor if it does not improve, spreads, affects the nails or scalp, or if you have diabetes or a weakened immune system.
References
- Centers for Disease Control and Prevention (CDC). Fungal Diseases.
- American Academy of Dermatology. Fungal infections.
- Mayo Clinic. Fungal infections.
- MedlinePlus, U.S. National Library of Medicine. Fungal infections.