Fungal Infections: Description, Causes and Risk Factors:
Fungal infections represent the invasion of tissues by one or more species of fungi. They range from superficial, localized skin conditions to deeper tissue infections to serious lung, blood (septicemia) or systemic diseases. Some fungi are opportunistic while others are pathogenic, causing disease whether the immune system is healthy or not.
Fungi are one of four major groups of microorganisms (bacteria, viruses, parasites, and fungi). They that exist in nature in one of two forms: as unicellular yeasts or as branching filamentous molds (also may be spelled as "moulds"). Some fungi are dimorphic - they change from one form to another depending on their environment. While yeasts cannot be seen with the naked eye, molds can be seen as the fuzzy splotches on overripe fruit or stale bread, as mildew in the bathroom shower, and as mushrooms growing on a rotted log. There are more than 50,000 species of fungi in the environment, but less than 200 species are associated with human disease. Of these, only about 20 to 25 species are common causes of infection.
Most fungal infections occur because a person is exposed to a source of fungi such as spores on surfaces or in the air, soil, or bird droppings. Usually, there is a break or deficiency in the body's immune system defenses and/or the person provides the "right environment" for the fungi to grow. Anyone can have a fungal infection, but certain populations are at an increased risk of fungal infections and recurrence of infections. These include organ transplant recipients, people who have HIV/AIDS, those who are on chemotherapy or immune suppressants, and those who have an underlying condition such as diabetes or lung disease.
Infections involving fungi may occur on the surface of the skin, in skin folds, and in other areas kept warm and moist by clothing and shoes. They may occur at the site of an injury, in mucous membranes, the sinuses, and the lungs. Fungal infections trigger the body's immune system, can cause inflammation and tissue damage, and in some people may trigger an allergic reaction.
Many infections remain confined to a small area, such as between the toes, but others may spread over the skin and/or penetrate into deeper tissues. Those that progress and those that start in the lungs may move into the blood and be carried throughout the body. Some fungal infections may resolve on their own, but most require medical attention and may need to be treated for extended periods of time. Those that penetrate into the body typically increase in severity over time and, if left untreated, may cause permanent damage and in some cases eventually be fatal. A few fungal infections may be easily passed on to other people, while others typically only affect the infected person.
Fungal infections may be categorized by the part of the body that they affect, by how deeply they penetrate the body, by the organism causing the infection, and by the form(s) that the fungi take. Some organisms may cause both superficial and systemic infections.
Certain factors or conditions can result in an overgrowth of fungus in the body. These include:
Taking antibiotics. Antibiotics can kill off “healthy” bacteria in the body, as well as bacteria that cause disease. When antibiotics kill the healthy bacteria, the normal balance of microorganisms in the mouth, vagina, intestines, and other places in the body is altered, resulting in an overgrowth of Candida albicans or other fungi.
- Having a weakened immune system due to certain conditions, such as HIV/AIDS or taking steroid medications or chemotherapy
- Having high blood sugar due to diabetes, which provides food for Candida albicans and encourages its overgrowth
- Fungal infections can also be passed from a pregnant woman to her infant during vaginal delivery or breastfeeding.
Symptoms of fungal infections differ depending on the type and severity of the infection, the area of the body affected, and individual factors.
Symptoms of athlete's foot include:
Itching of the feet.
Symptoms of jock itch most often occur in men and include:
Itching of the groin area.
- Red, scaly rash in the groin area.
Symptoms of ringworm include:
Red, itchy area on the scalp, often in the shape of a ring.
Symptoms of fungal infections that affect the mouth (oral thrush) include:
Lesions or sores that are raised, are yellow-white in color, and appear in patches in the mouth or throat and/or on the tongue.
- Sore, bleeding gums.
- Patches or lesions that become sore, raw and painful, making it difficult to eat or swallow.
Symptoms of fungal infections that affect the vagina (vaginal thrush) include:
Thick, white vaginal discharge that has a texture similar to cottage cheese.
- Vaginal irritation.
- Vaginal itching.
- Burning with urination.
Symptoms of fungal infections that affect the digestive tract (fungal gastroenteritis) include:
Diagnosing infections remains a problem in the management of fungal diseases, particularly in the immunocompromised host. Signs and symptoms are nonspecific, colonization is difficult to distinguish from invasive disease, blood cultures are commonly negative and patients are often unable to undergo invasive diagnostic procedures. This situation has led to the strategy of initiating empirical therapy in the high-risk patient. A variety of tests has been applied to several body fluids. At the simplest level, the clinician must be familiar with the appearance of various fungi in tissue. Non-culture methods include antibody- and antigen-based assays, metabolite detection and molecular identification. The latter includes PCR identification of fungal DNA from body fluid samples using conserved or specific genome sequences. Detection of glucan in blood has been achieved using crab amoebocyte lysate. With aspergillosis, predictive clinical correlates have been defined, respiratory tract cultures are highly predictive of invasive disease in the appropriate setting and certain CT scan findings enable early diagnosis. Bronchoalveolar lavage is also very useful. Galactomannan antigen testing of blood is routine in some European Centres, with EIA methodology supplanting agglutination because of apparently greater sensitivity. PCR has been made specific by genus-specific probes, with 100% sensitivity and reasonable specificity. In candidacies, the number of sites of colonization correlates with invasion. Tests for mannan antibodies and antigenemia are currently of interest. Metabolite assays appeared promising but have not been pursued commercially. In cryptococcosis, pronase treatment of serum has reduced false positives and false negatives, and improved reproducibility of titres. Birdseed agar improves culture specificity. In coccidioidomycosis, serology is the exemplar for all mycology. Gene probes have accelerated diagnosis by culture. In histoplasmosis, the antigenuria test's high sensitivity and specificity has dispelled the chronic confusion in interpreting antibody test results.
Some fungal infections are caused by normal flora and by fungi that are present throughout the environment; therefore, not every fungal infection can be prevented and some of them may recur after treatment.
Many superficial fungal infections will resolve with only a topical antifungal treatment, but some cases may require oral antifungal therapy. People with serious lung and systemic fungal infections will require oral and sometimes intravenous medications. The choice of which antifungals to use is based upon the doctor's experience, on the results of the fungal culture, and on the results of susceptibility testing, if it is performed.
Treatment length varies by type, location, and persistence of infection. Vaginal yeast infections, for instance, may require only a few days of therapy to resolve, while fungal skin infections may take a couple of months. Systemic infections may require consistent treatment for a couple of years in order to resolve and, in some cases, people with suppressed immune systems may need to be treated with a maintenance therapy for the rest of their lives. Occasionally, surgery may be necessary to remove fungal masses.
Unfortunately, fungal infections tend to recur after treatment in susceptible individuals. You can minimize your chances of recurrence by following these simple instructions:
For infection of the body, feet and groin:
Fungus does not like to live on dry, normal skin. Use a blow dryer on a low setting to dry the feet and groin area after bathing.
- Sprinkle a drying powder such as Zeasorb-AF or Tinactin on your groin, feet, and into your shoes.
- Wear cotton socks and underwear. Change them if they become damp from sweating.
- Avoid tight shoes and clothing, especially in the summer. If possible, wear sandals and loose-fitting underwear.
- Avoid going barefoot in public places (i.e. swimming pools, gym locker rooms, public showers).
For infection of the scalp or nails:
Discard or sterilize all hair combs and brushes.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.
- Keep finger and toenails trimmed short to prevent trauma.
- Use an antifungal cream on the feet to prevent spread from the nails to the surrounding skin. Use an antifungal powder in your shoes or replace the shoes you were wearing when your infection developed.
- Keep feet dry as above.
- Please keep in mind that nail fungus often does not bother patients except for its appearance. Many people choose not to treat fungal nail infections due to frequency of recurrence, cost, and risk of side effects from the medication.