The red itchy scalp is mostly considered to be caused by ringworm of the scalp, seborrheic dermatitis, folliculitis, contact dermatitis and other diseases. 1. Tinea capitis: tinea capitis is mostly caused by contact with pathogenic dermatophytes through the scalp, and patients will have symptoms such as red pimples, alopecia areata spots, scales, etc., and often have different degrees of itching. 2. Seborrheic dermatitis: the cause of the disease is not clear, with Malassezia colonization, lipid increase, skin barrier function is impaired, immune response and individual susceptibility. It occurs on the scalp. Patients are mainly characterized by red patches, scales, and itching. 3. Folliculitis: mainly due to bacteria and other pathogens infected hair follicles caused by inflammation. Patients mainly manifest as red papules, which may be accompanied by itching and other symptoms. 4. Contact dermatitis: if the scalp is stimulated by hair dye, shampoo and other external substances, the patient may appear erythema, papules, mild edema and other skin changes, accompanied by itching and other symptoms. There are many reasons for red itchy scalp, it is recommended that patients go to the hospital, clear causes, timely treatment.