Red spots on inner thigh

It is common to have red spots on the inner thighs, but they should not be underestimated. The red spots on this area may be caused by skin ringworm, which is mainly caused by bacterial infection. The most common area is the inner thighs, and it may also extend to the genitals, buttocks or around the anus. It is transmitted by cats, dogs, and people with ringworm. You should pay attention to stay away from bacteria sources and pay attention to personal hygiene.

reason

The main pathogens of tinea cruris are Trichophyton rubrum and Trichophyton mentagrophytes. Epidermophyton floccosum was also a common pathogen of tinea cruris in the past, but has become less common in recent years. Some other pathogens that can cause tinea corporis can also be the pathogens of tinea cruris, but they account for a small proportion. Traditional Chinese medicine believes that prolonged sweating is caused by exogenous wind evil.

examine

Tinea cruris is a skin disease that often occurs on the thighs, and sometimes can affect the perineum, mons pubis, perianal area, buttocks, scrotal folds, etc. It causes severe itching, and due to scratching, patients may develop secondary dermatitis, lichenification, or secondary infection.

feature:

(1) When tinea cruris first occurs, it appears as a slightly raised, red patch with clear edges. It gradually expands and becomes covered with scale, which gradually changes from red to brown or skin color.

(2) The center of the lesion gradually heals automatically and spreads to the periphery. The inflammation at the edge of the erythema is more obvious, and there may be rashes, blisters, scabs, and even erosions on it, forming a ring.

(3) Temporary pigmentation will remain after healing, and the itching symptoms will be severe.

When tinea cruris first occurs, redness and small papules appear on the inner side of the thigh near the scrotum, followed by the formation of small white scales on top of the papules. The rash gradually spreads to the surrounding area with clear boundaries. During the progressive stage, papules, blisters, and scales may appear simultaneously at the edges, and pustules may occasionally be seen. The level of pruritus perceived by individuals varies greatly. In severe cases, the itch is unbearable, while in mild cases, there is no itch at all. Frequent scratching may cause lichenification and pigmentation. The lesions may also extend to the lower abdomen, perineum and buttocks. The skin of the scrotum and penis may also be involved.

The condition is closely related to the season. It tends to spread and worsen in summer, with significant itching, while it can be naturally relieved and the condition becomes stable in winter. If this disease is not treated in time, it may persist for a long time.

The diagnosis of typical tinea cruris is not difficult. It is mainly based on the presence of symmetrical or unilateral, clearly demarcated annular inflammatory lesions in the pubic and femoral areas, with disseminated papules, blisters, and scales at the edges. Direct microscopic examination of the scales and blisters can reveal fungi, and the positive rate of microscopic examination is very high.

Differential Diagnosis

Differential diagnosis of inner thigh erythema:

It is not difficult to diagnose tinea cruris, but it should be carefully differentiated from some skin diseases, otherwise it will be difficult to achieve targeted treatment. Skin diseases that are easily confused with tinea cruris include:

1. Seborrheic dermatitis: Sometimes it can also invade the pubic and femoral areas. The rash is light red spots with desquamation. Some are ring-shaped with clear boundaries, but direct microscopic examination for fungi is negative.

2. Erythrasma: A skin disease caused by a bacillus, commonly found in the armpits, thighs, etc. The skin in the affected area is brick red, with no inflammatory ring on the edge and no itching. Direct microscopic examination of fungi is negative.

3. Psoriasis: commonly known as psoriasis, it can invade the thighs, manifesting as annular or plaque-like erythema, generally with thicker scales on the surface. The same rash may also occur in other parts of the body.

4. Scrotal eczema and dermatitis: The skin lesions are mainly lichenified or eczematous, with unclear edges, no tendency for the center to heal on its own, significant itching, and the development of the skin lesions is not closely related to the season. It should be noted that tinea cruris is prone to eczema-like changes after intense scratching, hot water washing or use of highly irritating topical medications. The course of the disease is protracted and recurrent, making it difficult to treat.

5. Vitamin B2 deficiency: It is a syndrome of skin, scrotum and oral cavity caused by lack of vitamin B2 (riboflavin) in the body. The main manifestation is scrotitis. It starts with diffuse pink patches on the scrotum with clear boundaries and slightly higher edges above the skin surface. They are covered with grayish white scales or thick brown-black crusts. Bacterial examination of the scales is negative. Glossitis and angular cheilitis are combined and tend to occur collectively in the same catering unit.

Mitigation methods

Frequent moisture in the pubic and thigh area is one of the conditions for the onset of tinea cruris. People who are fat and sweat a lot are more likely to suffer from this disease than those who are thin. Therefore, the area should be kept dry. After bathing, you can sprinkle powder such as commercially available talcum powder locally. The underwear you wear on a daily basis should not be too tight or too thick, and should be breathable. Most cases of tinea cruris may be transmitted from tinea manuum and tinea pedis themselves. Therefore, it is important to actively cure tinea manuum, tinea pedis and other tinea diseases.

(1) Maintain self-discipline and refrain from having improper sexual relations with others. Do not use other people's underwear, panties and toiletries.

(2) Change underwear frequently, keep the vulva clean, and wash and dry clothes and quilts frequently.

(3) Reduce sweating and promote evaporation at the base of the thigh. Try to keep the perineum dry and wear loose fitting underwear that is not too tight.

(4) If you suffer from onychomycosis, tinea manuum, or tinea corporis, you should actively seek treatment to prevent the disease from being transmitted to the pubic area through your hands.

Be careful of jock itch during the rainy season: Beijing is rainy and humid in summer. In addition, more and more people like to wear tight pants, jeans, nylon underwear and tights, so more and more people are infected with jock itch. Doctors call for people to take preventive measures as the rainy season is a high-risk period for tinea cruris.