Itchy skin a red spot when scratching the situation, consider and urticaria, contact dermatitis, pruritus and other factors related. You can choose to take oral antihistamines, topical glucocorticoids and other medications. 1. Urticaria: an edematous mass raised on the surface of the skin and mucous membranes, and contact with allergens, etc., can cooperate with the doctor to choose to apply glycerine lotion, oral loratadine, cetirizine and other antihistamine treatment. 2. Contact dermatitis: it is also caused by skin contact with external substances and inflammatory skin diseases, so there will be itchy skin, a red spot when you scratch the symptoms, you can cooperate with the doctor to take oral antihistamines, topical mometasone furoate gel and other glucocorticosteroid drugs treatment. 3. Pruritus: patients may be due to dry skin, contact with irritants and other factors, thus appearing itchy skin, scratching the skin can appear skin breakthrough crust, so can lead to the phenomenon of a red spot when the skin is scratched, can be used externally to repair the skin barrier such as moisturizing creams, and if necessary, the application of hydrocortisone, dexamethasone, and other glucocorticoid drugs treatment. All of the above medications should be used under the guidance of a doctor to avoid self-medication. It is recommended to cooperate with the doctor to clarify the specific causes before treatment.