What Is the Main Cause of Fungal Infection?

Medically Reviewed on 1/4/2022
Fungal infection - ringworm
The main cause of fungal infection is compromised immunity (either local immunity over the skin or mucous membranes or systemic immunity as seen in the case of certain conditions such as diabetes and HIV/AIDS).

Fungal infections (especially skin lesions) are common and occur in every person at one time or another.

  • A moist environment, humid climate, wearing synthetic clothes, sweating excessively, or certain personal habits may make you prone to an occasional superficial fungal infection.
  • Many studies report that neutropenia (reduced white blood cell count) is a risk factor for systemic fungal infections such as aspergillosis, candidiasis, and mucormycosis in many individuals.

The main cause of fungal infection is compromised immunity (either local immunity over the skin or mucous membranes or systemic immunity as seen in the case of certain conditions such as diabetes and HIV/AIDS).

If you get recurrent fungal infections over the skin and other body parts, the cause may be one of the following:

  • Recent antibiotic course: A prolonged systemic antibiotic course can make you more likely to get a yeast or fungal infection due to unintentional death of the healthy body microbes.
    • Women may get vulvovaginal candidiasis, and men may have balanitis (fungal infection of the foreskin and head of the penis) after the course of a broad-spectrum antibiotic.
  • Personal habits: Frequent handwashing, not taking a shower post-workout, wearing sweaty clothes all day, and sweaty socks may make you prone to fungal infections in the groin (Jock’s itch), skin (ringworm), toe spaces (tinea cruris), and scalp (tinea capitis).
  • Weather: Many fungal infections are more common in summer and monsoons when the weather is moist and damp.
    • The fungus that causes Valley fever is found mainly in the southwestern United States.
    • Histoplasmosis and blastomycosis occur most often in the eastern United States.
  • Occupation: Some professions may increase your exposure to fungal spores such as digging, gardening, cleaning chicken coops, and visiting caves.
    • Histoplasma is seen in soil that contains bird or bat droppings.
    • Similarly, people who need to dip their hands in water are more prone to fungal skin infestation.
  • Pets: Sometimes, you may get ringworm from your dogs and cats. Adult animals do not always show signs of ringworm infection but may pass it on to humans.
  • Medications: Medicines that weaken your immune system may increase your risk of a fungal infection.
    • A high-dose steroid therapy, immunomodulatory, and chemotherapy may reduce your white blood cell count and make you prone to fungal infection. 
    • Many individuals who take steroid inhalers for asthma complain of oropharyngeal candidiasis.
    • Individuals who were given high-dose steroids for COVID-19-related lung complications developed a deadly fungal infection in the sinuses and lungs (mucormycosis).
    • Recurrent use of proton pump inhibitors for acid reflux may lower stomach acidity and make you prone to gastric or intestinal candidiasis.
  • Individuals with HIV infection: People with HIV (particularly those with CD4 counts less than 200) are at a risk of fungal infections.
  • Diabetes mellitus: Individuals with uncontrolled sugars often develop fungal infections in the vagina, penile end, or skin. In severe cases, they may develop a fungal infection of the esophagus or gastrointestinal tract.
  • Transplant recipients: People who have recently had an organ transplant or a stem cell transplant will have weakened immune systems due to procedural stress and immunosuppressants taken after the procedure.
  • Chemotherapy: Individuals who undergo chemotherapy or radiation treatments have low white blood cell counts.
    • These treatments may increase your risk of fungal infection; hence, you need to be extremely careful with your exposure to the outside world.
  • Extremes of age: Fungal infections may be seen in newborns who do not have a well-developed immune system.
    • It may be seen especially in the oral cavity of newborns, which they may transmit to the mother (nipple candidiasis) during breastfeeding.
    • These infections may be seen in the elderly, especially in those with dementia or Parkinson’s disease.
  • Cancer: People with advanced cancer have poor immunity due to the disease and cancer therapy. These individuals are prone to deadly systemic fungal infections.
  • Pre-existing conditions: Diseases, such as ulcerative colitis and Cohn's, predispose candida to build up in the gut because there are existing lesions in the gut that can be easily infested by fungi.
    • Similarly, those with extensive burns or cancerous ulcers may be prone to systemic fungal infestations.

What kills fungus in the body?

The body has multiple lines of defense against fungal infection, which include:

  • Intact skin: Provides a strong physical barrier against any invasion.
    • Additionally, it consists of many commensal (good) bacterial colonies that reside over the skin. These bacteria prevent the adhesion of fungus to the body. These synthesize compounds that maintain the pH of skin at the level of about 5.5, which is not conducive to fungal growth.
  • Innate Immunity: In the case of systemic fungal infections, macrophages, natural killer cells, dendritic cells, and neutrophils are the first line of defense against inhaled fungal spores.
    • These identify proteins over fungal spores and cell walls and launch an immune attack by secreting chemicals such as IFN-γ and interleukins that have the potential to destroy the fungus.
  • Adaptive immunity: When the fungus manages to invade the first two lines of defense and cannot be quickly controlled, adaptive immune cells (CD4+ T cells) come into play.
    • These activate other T cells and secrete the cytokines IFN-γ and TNF-α, which activate innate immune cells, trigger antibody production and activate the release of antimicrobial peptides from endothelial cells in the body to fight the fungus.

When these defenses are inadequate to ward off the fungus from the body, your doctor may prescribe oral or topical antifungals. These act by destroying the fungal cell wall and making the fungus susceptible to bodily defenses.


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What foods help fungal infections?

Many practitioners of complementary medicine advocate a “candida diet” to help against fungal infections.

  • They advocate a diet that completely cuts out “sugar,” “refined flour,” “yeast” (bread), and “cheese.”
  • These foods supposedly increase the colonization of candida in the gut by damaging the “good gut bacteria.”

The “candida diet” consists of foods rich in soluble fiber (whole grains and seeds), polyphenols (colored fruits and vegetables), and antioxidants (nuts, oils, and fruits) that help maintain the gut immunity by the colonization of good gut bacteria.

Moreover, the diet advises the inclusion of probiotics (curds, kefir, buttermilk, and yogurt), coconut oil, olive oil, and non-caffeinated drinks, such as green tea, in the diet.

Although large-scale evidence that supports the efficacy of such a diet in warding off fungal infections is missing, the inclusion of high-fiber foods and cutting out sugars and refined flours are definitely beneficial for overall health. This may indirectly help keep away infections by normalizing your blood sugar levels and strengthening your immunity.

Why is my fungal infection not going away?

If you find your fungal infection is not getting better despite medications and dietary modifications, the following conditions may be the culprits:

  • Personal habits: Make sure you wash your sweaty gym clothes, caps, and socks with hot water, antibacterial liquids, and detergents. The persistence of fungal spores in clothes may cause reinfection. Use antiperspirant sprays and powder if needed and prescribed by your dermatologist.
  • Not using personal protective equipment: The use of sterile and disposable gloves while digging, gardening, and dipping hands in water or masks while working in a high-spore environment may prevent unnecessary exposure to spores.
  • Undiagnosed health conditions: Make sure you check your sugars and thyroid levels if you get recurrent fungal infections of the skin. If you have a family history of cancer, you may require specific cancer screening as well.
  • Resistant fungus: Many times, improper treatment or poor compliance causes the fungus to become resistant to treatment. Such infections need to be investigated and treated more aggressively.
  • Drugs: Concurrent use of steroids (ointments or tablets) along with antifungal therapy often causes the fungus to recur. It is better to avoid antibiotics and steroids unless they are really required.
Medically Reviewed on 1/4/2022