Thighs long heat rash that prickly heat, also known as corn grain rash, mainly due to the high temperature, hair follicles sweating caused by the blockage of the sweat gland ducts, you can through the general treatment, topical drugs, systemic medication and other measures to regulate. 1. General treatment: first of all, you should avoid working and living in a hot environment again, keep your skin clean and dry, and avoid scratching. 2. Topical medications: prickly heat powder, glycerite lotion, peppermint tincture, hydrocortisone ointment, tretinoin cream, etc.; if there is secondary infection, erythromycin ointment, clindamycin cream and so on. 3. Systemic medication: severe itching can take cetirizine, chlorpheniramine and other antihistamines; secondary bacterial infection can take amoxicillin, cefazoxime and other antibiotics. It is recommended to go to the hospital for examination first, and the drugs need to be used under the guidance of a professional doctor.