Fungal Infections

Superficial fungal infections of skin, nail, and hair

Superficial fungal infections may be caused by both yeast and mold forms of fungi. Skin is normally populated with a mixture of microorganisms 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 compromised, then any of the microorganisms present can cause a wound or skin infection. If there is a shift in the balance of the microorganisms, 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 can cause diaper rash. In women, it 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. Candidiasis can also cause a variety of other infections, including nail infections, and can become systemic – especially in those who are immunocompromised. It is currently the fourth most common cause of hospital-acquired septicemia in the United States.

Fungal (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.

Deep Tissue, Blood, Lung and Systemic Fungal Infections
A variety of fungi can cause deep and systemic infections. Some are found throughout the U.S. while others are found in specific regions. People frequently become infected because they come in contact with the environment where a fungus grows, such as infected soil. Lung infections typically start with the inhalation of fungal spores. With lung infections, and with fungal infections that have spread below the surface of the skin, the invading fungi have the potential to disseminate from the original infection location and move to the blood (septicemia) and/or spread throughout the body – into organs, tissues, bone, and sometimes into the meninges that cover the spinal cord, and into the brain.

In many patients 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 other patients, fungi may cause infections that remain localized at the initial site of the infection and do not spread (the organisms are walled off in granulomas). However, people with these localized infections may, at some point in their life, become immunocompromised and the long-standing, silent chronic fungal infection may then become an active acute infection. Some 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 compromised immune systems such as those with HIV/AIDS. Both acute and chronic fungal infections can cause permanent lung, organ, and bone damage and can be fatal. Common deep or systemic infections include:

• Aspergillosis, caused by Aspergillus fumigatus or several other Aspergillus species. These 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, such as woodland areas of the south-eastern and south-central United States.
• Coccidiomycosis, caused primarily by Coccidioides immitis found in arid soil of the southwestern U.S., Mexico, and South America.
• 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.
• Histoplasmosis, caused by Histoplasma capsulatum found primarily in the east and central U.S.; typically affects the lungs.
• Candidiasis, caused by Candida species, which are part of the normal human flora, are found worldwide. Infections occur in the moist mucous membranes of the body.
• Pneumocystis pneumonia, caused by Pneumocystis jorveci (formerly known as Pneumocystis carinii), found worldwide and most commonly affecting those with compromised immune systems, including those with HIV/AIDS.