Definition

Tinea refers to a skin infection caused by fungi from the dermatophyte group. Tinea corporis affects the body, arms, and legs. Meanwhile, tinea cruris refers to a fungal infection in the groin or inner thigh area, and tinea manus refers specifically to a fungal infection of the hands.

Causes

Tinea corporis, tinea cruris, and tinea manus are caused by dermatophyte fungal infections. These fungi are classified into three types based on their source of transmission:

• Anthropophilic: Transmitted between humans. The most common cause of tinea corporis, cruris, and manus is Trichophyton rubrum.
• Zoophilic: Transmitted from animals to humans. Microsporum canis from dogs and cats can cause tinea corporis and manus.
• Geophilic: Transmitted from soil to humans. Examples include Microsporum gypseum, which can cause tinea corporis; Chrysopodium keratinophilum, which may cause tinea corporis and manus; and Microsporum fulvum.

Risk Factor

Anyone can develop a fungal infection. The risk of tinea corporis is higher among those living in warm climates, in close contact with infected people or animals, sharing clothes, sheets, and towels with an infected person, participating in contact sports (such as wrestling), wearing tight clothing, and having a weakened immune system.

The risk for tinea cruris is higher in men, teens, or young adults, those who wear tight underwear, are overweight, sweat heavily, have a weakened immune system, or have diabetes.

The risk of tinea manus is higher in people who care for or are frequently around animals that may carry fungi, participate in contact sports, and use public bath facilities.

Symptoms

The symptoms of tinea corporis, cruris, and manus are generally similar, though their location differs.

Tinea Corporis Symptoms:

• Scaly, ring-shaped patches on the body, particularly on the buttocks, torso, back, arms, and legs
• Itchiness
• Clear or scaly skin within the ring, which is formed by red, raised, or clear blisters
• The ring enlarges over time
• Flat, round, itchy patches

Tinea Cruris Symptoms:

• Starts with a red area in the groin fold, which can spread to the upper thigh, forming a half-ring shape
• The red area may take on a ring-like form with blistered edges
• Itchiness or a burning sensation, with flaking or scaling skin in the area

Tinea Manus Symptoms:

• Small, enlarging infected areas on the hands
• Begins on the palm, potentially spreading to the fingers and back of the hand
• The infected area becomes itchy, red, and scaly
• Peeling skin
• Often affects only one hand and may present with clear-fluid-filled blisters

Diagnosis

Diagnosis of tinea corporis and cruris typically relies on symptoms, history, and physical examination. Laboratory tests can confirm the diagnosis. Scrapings from the ring edges are treated with potassium hydroxide (KOH) to kill skin cells, and then examined under a microscope to detect the fungus.

For tinea manus, which may resemble hand dermatitis, KOH skin scrapings and, if needed, a biopsy can be performed to rule out other causes of itching and redness. Besides these tests, skin scrapings or tissue samples can be used for culturing the fungus, a process that may take 2-6 weeks but is primarily used in cases that don’t respond to treatment or for research purposes.

Management

Tinea corporis, cruris, and manus are commonly treated with topical antifungal medication. Since dermatophytes feed on skin keratin, they expand in search of more keratin. Therefore, antifungal ointments are applied to the ring's outer edge, where the fungi are most concentrated, typically for 2-3 weeks.

If the infected area is extensive or topical treatments are ineffective, a doctor may prescribe oral antifungal medication. However, these drugs should only be taken as prescribed, especially if the patient is pregnant, breastfeeding, or regularly taking other medications.

To support treatment, keep the infected area dry and clean, and avoid tight clothing. If you have a compromised immune system due to diabetes, HIV, or long-term steroid use, consult your doctor regarding managing your health conditions.

Complications

Tinea corporis, cruris, and manus rarely cause complications unless diagnosis and treatment are delayed. If an infected area is injured, the fungus can penetrate deeper, infect surrounding tissue, and lead to an abscess (pus-filled cavity).

Complications may also occur if the infection is mistakenly treated with topical steroids, which can mask symptoms and make diagnosis harder. Long-term steroid use may cause skin thinning (atrophy) and enlarged blood vessels (telangiectasia).

Prevention

Preventing tinea corporis, cruris, and manus involves:

• Personal and Community Care: Recognize fungal infections in both humans and animals, especially if you have pets. Teach children about fungal infections, symptoms, and prevention.
• Hygiene: Wash hands regularly, maintain cleanliness in shared areas, shower immediately after contact sports, and keep uniforms and sports gear clean and dry.
• Keeping Skin Cool and Dry: Avoid tight or heavy clothing, especially in warm, humid environments. Dry off promptly after sweating.
• Avoiding Infected Animals: Infected animals may have bald patches on their skin. If you suspect your pet or another animal is infected, consult a veterinarian.
• No Sharing of Personal Items: Avoid sharing clothes, towels, combs, sports equipment, and similar items, and avoid borrowing these items from others.

When to see a doctor?

If you experience itching along with red, ring-shaped patches on your body, groin, or hands, consult a doctor. If you have been treated and maintained cleanliness but symptoms persist, seek medical advice to adjust the treatment.