Baby face and legs on the red rash, may be allergic dermatitis, keratosis pilaris, cornrows and other diseases caused by, should consult a doctor in a timely manner, to clarify the cause of the targeted treatment. 1. Allergic dermatitis: allergens stimulation caused by a relatively common skin disease, patients will have skin rashes, itching, the child will also have more than crying, should find out the source of the allergy and to avoid re-exposure, if necessary, the use of Benadryl, cetirizine and other drugs for treatment. 2. Keratosis pilaris: baby face and legs on the rash may also be caused by keratosis pilaris, which is a chronic follicular keratosis pilaris, lesions will be aggravated in the winter, summer to reduce the topical use of retinoic acid, urea and other drugs for treatment. 3. Corns: baby face and legs on the red rash may also be caused by corn rash, mostly due to a long time in a high humidity and high temperature environment, should pay attention to ventilation, wear appropriate clothing, general conditions without treatment, in severe cases can be used topical glycerite lotion or mupirocin ointment. All of the above drugs should be used under the guidance of a doctor to avoid adverse consequences.