If you have ringworm on your thigh root, it is not advisable to secretly apply medicine on yourself

Reviewer: Zhang Shuyuan, Chief Physician, Beijing Huayi Integrated Traditional Chinese and Western Medicine Dermatology Hospital

Xiao Ling is an office worker who often sits all day. Recently, she found that the roots of her thighs were red and itchy, and she felt embarrassed to scratch them.

Xiao Ling thought it was eczema, so she went to the pharmacy and bought some ointment for eczema. However, after applying it for a few days, it didn't get better, but got worse. What's going on?

In fact, Xiao Ling was not suffering from eczema, but a type of ringworm that many people who sit for a long time are prone to, called tinea cruris.

1. Tinea cruris: Tinea corporis in special parts of the body

Tinea cruris refers to a dermatophyte infection that occurs in the groin, perineum, around the anus, and buttocks. It is a type of body tinea that occurs in a specific area.

Initially, erythema appears in the groin area with dandruff on the surface. The lower edge is usually more obvious, while the upper edge is not very obvious. The middle of the erythema may recover on its own, but the symptoms on the edge will be more severe, and it is often accompanied by papules, papulovesicles and blisters, forming a ring-shaped or semi-ring-shaped lesion with clear boundaries.

Tinea cruris usually starts on one side and then slowly spreads to both sides, with the edges constantly expanding outward. It can spread down the thigh or up the groin, and may even spread to the abdomen, or infect the private parts and buttocks.

Generally speaking, because the affected area of ​​tinea cruris is relatively moist, has poor air permeability, is prone to sweating, and is often rubbed, it is easily worn out and then erosion or eczematous changes occur, and the itching will become more severe.

Many people can't help scratching, but it is recommended not to scratch, because if you scratch, the fungus will run to your hands, and your hands will touch other parts and get infected. If you really can't help it, wear disposable gloves before scratching.

Because of the special location of tinea cruris, many people find it difficult to talk about it. They usually buy ointments and apply them themselves. However, because they are not very targeted, the disease is prone to recurrence and daily life is greatly affected.

2. The main causes of tinea cruris

The main cause of tinea cruris is fungal infection, with Trichophyton rubrum being the most common. Others include Trichophyton mentagrophytes, Trichophyton verrucosum, Microsporum canis, and Epidermophyton floccosum.

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Because the above-mentioned fungi like to grow in a warm, humid and poorly breathable environment, tinea cruris is prone to occur in hot summer and autumn seasons and in humid and hot areas.

Based on this characteristic, we should pay attention to wearing loose and breathable clothes, maintain good hygiene habits, and wash ourselves clean in time after exercise.

Fungal infection may come from oneself, others, their belongings, animals, etc. As long as you touch a place with fungal filaments or spores, you may be infected.

Common ways of fungal transmission include: ① fungal infection on a part of one's own skin; ② touching the skin lesions of a patient with tinea cruris; ③ using items used by a patient with tinea cruris; ④ contact with small animals that carry dermatophytes or already have symptoms of infection.

Therefore, try not to share personal items such as towels and clothes with others, and treat tinea pedis and tinea manuum as soon as possible. People who keep pets at home should also check their pets regularly, and disinfect items that the pets have touched in time to reduce the risk of infection.

3. People who are susceptible to tinea cruris

The susceptible groups of tinea cruris are mainly the following categories: ① adolescents and young adults; ② fungal infection has occurred in a certain part of the body; ③ obese people; ④ people with well-developed sweat glands; ⑤ people with low immunity, excluding those with diabetes, tumors, and long-term use of glucocorticoids or immunosuppressants; ⑥ the incidence rate in men is higher than that in women; ⑦ the living environment is hot and humid, so the incidence rate in southern China is higher than that in northern China; ⑧ people with bad living habits, such as those who like to wear tight clothes and like to share personal belongings with others.

If you belong to one of the main groups listed above, there is no need to panic too much. Just pay attention to exercise more, pay attention to hygiene, develop good living habits, and seek medical attention in time if you find any corresponding symptoms.

Treatment of tinea cruris

If you have tinea cruris, you should seek medical attention in time and follow the doctor's advice to actively cooperate with the treatment. The treatment principle is mainly to eliminate pathogens, quickly relieve symptoms, remove skin lesions, and prevent recurrence.

Generally, topical medications, oral medications, or a combination of both are used, but individualization should be emphasized.

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First, local treatment is performed. Topical antifungal drugs are the first choice, 1 to 2 times a day, and the course of treatment is 2 to 4 weeks. Imidazole drugs and acrylamide drugs are the most commonly used in clinical practice.

Imidazole drugs include miconazole, ketoconazole, luliconazole, etc. Allylamine drugs include terbinafine, butenafine and naftifine, etc. [1]

For local treatment, you must strictly follow the course of treatment, and follow up in time. Adjust the medication in time according to the doctor's instructions to achieve a complete cure and prevent recurrence. Never stop taking the medication on your own just because the itching stops.

If topical medications are ineffective, skin lesions are widespread or recurrent, or the patient has a low immune system, systemic antifungal drugs can be used.

Commonly used drugs include terbinafine and itraconazole. The dosage of terbinafine for adults is 250 mg/d, and the course of treatment is 1 to 2 weeks. The dosage of itraconazole for adults is 200 to 400 mg/d, and the course of treatment is 1 to 2 weeks.

If the patient has chronic skin diseases such as eczema, atopic dermatitis, psoriasis, etc., it is recommended to first undergo antifungal treatment and appropriately extend the course of topical medication.

If patients have difficulty adhering to topical antifungal medications due to frequent use or long courses of treatment, oral antifungal drugs may be considered to improve efficacy [1].

The elderly, children, pregnant and lactating women, and people with immunodeficiency should be more cautious when using medications. Never use medications when the specific disease is unknown. Go to a regular hospital for examination and follow the doctor's advice for treatment.

References

Chinese tinea corporis and tinea cruris diagnosis and treatment guidelines working group. Chinese tinea corporis and tinea cruris diagnosis and treatment guidelines (primary practice version 2022). Chinese Journal of Mycology, 2022, 17(3): 177-182.