Ringworm - Causes, Symptoms and Treatments
Ringworm is a fungal infestation of the skin of the scalp or body. It is called this because of the round or ring-shaped mark often observed. No worm is involved!
There are many forms of superficial (surface) fungal skin infection, specific to the body areas that they affect:
- Scalp – tinea capitis
- Groin – tinea cruris (“dhobi itch” or “jock itch”)
- Beard – tinea barbae
- Hands – tinea manuum
- Feet – tinea pedis (“athlete’s foot”)
- Body – tinea corporis
- Face – tinea faciei/facialis
- Upper arms, chest and back – tinea versicolor
- Deep and systemic (whole-body) fungal infections are not dealt with here.
Fungi are everywhere around us. They exist naturally in our environment, as well as on and in our bodies, and do not normally cause disease. They thrive in warm, moist conditions, including warm, moist areas of the body such as the groin or feet.
Fungi can live on objects, animals or people for several months, and can be transferred quite easily from one person to another. However, this does not mean that the fungus will necessarily infect the other person. Some people are more susceptible, e.g. people whose immune systems do not work as well as they should. In such people, the presence of fungi on the body will result in fungal infection.
Most cases of fungal skin infection are caused by a dermatophyte (skin fungus) called Trichophyton rubrum. Dermatophytes attack the body’s keratin-containing outer tissues, but cannot invade the cells. (Keratin is a protein found in skin, nails and hair.)
Tinea versicoloris is a result of overgrowth of the fungus Malassezia furfur.
Symptoms of ringworm of the skin may include:
- Red patches with scaling, pustules and crusts
- Itchy rash that spreads rapidly
- Rash resembling a ring, with a clear centre and elevated, red, scaly border
- Patches of rash with a border that is not clearly distinguishable (some cases)
- Exacerbation of the rash after exposure to the sun (uncommon)
Ringworm of the scalp and beard:
- One or more round or oval patches of baldness on the scalp, beard or moustache
- Hair loss (temporary or permanent)
- Flakes resembling dandruff on the hair
- Irritation of the scalp, beard or moustache
- Crusted, broken or matted hair
- Black dots on the scalp where hair has broken off at the roots (less common)
- Swollen lymph nodes in the neck (occasional)
Ringworm of the groin:
- A rash in the groin, in skin folds, and on inner thighs or buttocks (usually not on the penis or scrotum)
- A well-defined border around the rash, with scaling or tiny blisters
- A red-brown centre inside the rash
- Simultaneous occurrence of athlete’s foot (some cases)
Ringworm of the hand:
- A rash on the palm or back of the hand (rare)
- Rash on palm: may be dry and scaly
- Rash on back of hand: may be scaly, with tiny blisters around the edges
- Fingernail infection (some cases)
- Simultaneous occurrence of athlete’s foot (some cases)
- Rash usually affecting the spaces between the third, fourth and fifth toes
- Red, scaly skin
- Macerated skin (whitish in colour due to moisture)
- Signs of fungal infection in toenails
Tinea versicolor (also called pityriasis versicolor):
- Rash consisting of white, scaly spots on the upper arms, chest and back
- Some people with fungal infections have an allergic reaction (called id reaction) on a different part of the body. In ringworm of the scalp, the id reaction usually occurs on the face.
Ringworm commonly infects children. Scalp ringworm is almost exclusively seen in young children.
Ringworm of the groin (dhobi itch) is seldom seen in women.
The first sign of ringworm of the scalp may be dandruff-like flakes appearing on the hair. Round and/or oval bald patches may appear. The skin may feel itchy and may be red and peeling. The rash may gradually spread over a large area if left untreated. Once the hair is infected, it becomes brittle and breaks off near the root, resulting in bald spots. If treated early, the baldness is temporary. The skin of the infected area may become very tender if swollen areas and blister-like bumps with pus develop. The blisters may become infected. If left untreated, ringworm of the scalp or beard may result in scarring and permanent hair loss.
Ringworm of the skin starts as a small patch that is itchy, red or scaling. The rash may spread over a large area. Symptoms are aggravated by clothing rubbing against the rash, and by sweat, heat and humidity. As the infection becomes worse, the ring-like pattern and red-brown colour become more distinct. If left untreated, blisters and cracks may become infected with bacteria. Ringworm can spread to other parts of the body.
- Previous fungal infection
- Impaired immune system, owing to illnesses such as diabetes, cancer or AIDS
- Living in a warm, damp climate
- Keeping skin damp or wet for long periods of time
- Wearing tight-fitting clothes and shoes
- Contact with animals and people who may carry the fungi without necessarily being infected themselves
- Contact with objects that have the fungi on them, eg. shoes, hats, towels and bed linen
- Men are more prone to ringworm of the groin.
When to see a doctor
Call your doctor if:
- The skin on the scalp, under the beard or on the body is scaling, peeling, itchy, red and swollen, or if blister-like bumps with pus develop.
- There are dandruff-like scales that do not disappear after two weeks of treatment with anti-dandruff preparations.
- There is patchy hair loss.
- There are signs of a bacterial infection, such as increased pain, swelling, redness, tenderness and heat; red streaks extending from the area; a discharge of pus; and a fever with no other identifiable cause.
- There is no improvement after two weeks of treatment with non-prescription medication.
- The infection is spreading.
- There is persistent, severe or recurring infection.
Ringworm is diagnosed on the basis of a medical history and an examination of the infected area. In addition, tests may be done on a sample of the infected hair or skin to confirm the diagnosis:
- A KOH (potassium hydroxide) preparation can determine if a fungus is causing the condition. This test is done in a clinic or a doctor’s surgery. This involves the doctor scraping the skin with a blade and examining the debris under a microscope.
- A fungal culture may be done to determine if a fungus is causing the condition and, if so, which fungus it is.
- Wood’s Light Examination may determine the presence of fungi on the scalp or beard. In this test, a fluorescent light is shone onto the hair; some fungi will make the hair fluoresce or glow in the light.
- If secondary infection is suspected, a bacterial culture may be done.
- Rarely, the doctor may take a skin biopsy for a microscopic study.
Home treatment focuses on preventing re-infection and stopping the spread of the infection:
- Floors and soft furnishings should be vacuumed or steam-cleaned.
- Dilute bleach can be used to clean floors that may be contaminated.
- Pets should be checked by your veterinarian for signs of infection.
Medication for the treatment of ringworm usually consists of non-prescription anti-fungal preparations that can be applied to the infected area:
- Treatment often takes weeks, and should continue for some time after the rash disappears.
- Treatment should extend beyond the visible border of the rash.
- Medication to be taken orally may also be prescribed by your doctor; ringworm of the scalp is usually treated with griseofulvin.
- Secondary infection may require antibiotic treatment.
- Selsun or ketoconazole shampoo may help, but is not sufficient treatment by itself.
- Treatment for athlete’s foot is now available as a once-off dose.
- Avoid close contact with people who have ringworm of the scalp, beard or skin.
- Avoid petting animals that have bald or mangy spots on their coats.
- Wear fresh underwear and socks daily.
- Do not share hats, coats, brushes and bed linen with someone who has ringworm.
- Disinfect sports equipment like mats.
- Avoid the use of products such as perfumed hair ointment that can promote the growth of fungi.
- Keep your skin clean and dry.
- A person may be a carrier of fungi without even being aware of it. Therefore, all the family members of an infected person should be tested for fungal infection.
- If you have athlete’s foot, put your socks on before your underwear to avoid infecting your groin area.
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