Itchy thighs can be caused by contact dermatitis, ringworm, folliculitis and other factors. 1. Contact dermatitis: frequent contact with sensitizing or irritating substances can lead to repeated localized allergic or irritating reactions in the thighs, which can lead to frequent itching of the thighs, possibly accompanied by redness and other symptoms. 2. Ringworm: usually associated with fungal infections, can make the thighs localized red patches, clear boundaries, accompanied by itching, peeling and other symptoms, excessive scratching, but also lead to aggravation of the lesions. 3. Folliculitis: prolonged inattention to thigh hygiene may repeatedly induce folliculitis, will often appear itchy symptoms, with the aggravation of the lesion, the localization will appear abscess, accompanied by pain, redness and other symptoms. The thighs are always itchy indicating the existence of abnormal conditions, it is recommended to consult a doctor for timely examination and treatment.