Red spots on the inner thigh

We all know that the flesh on the inner thigh is relatively fragile. Because this part is not exposed to the outside, the skin in this area is relatively tender, which makes it easy to get various skin diseases. The inner thigh is also connected to the private parts, and it is easy to be invaded by bacteria in the private parts. So what are the red spots on the inner thighs?

Red patches on the inner thighs are common in tinea cruris. Tinea cruris refers to a skin ringworm disease that occurs in the scrotum and groin areas of the human body. This dermatophyte disease caused by dermatophyte infection mainly occurs in the thigh (on both sides of the inner thigh), hence the name tinea cruris. This type of ringworm can spread to the perineum, perianal area, and buttocks, so it is also called tinea pubis and tinea cruris. The main symptom is obvious local itching. The disease is prone to relapse. It is mostly caused by contact with patients with ringworm, or through cats, dogs, etc., or indirectly through clothing and utensils, or by first having tinea pedis and then spreading the infection through scratching. In summer, the climate is hot and humid, and the human body sweats a lot, especially in the thighs. If you don't take a shower in time, or wear tight underwear and a lot of sweat has no time to evaporate, you are likely to get this disease.

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.