Skin redness after scratching may be due to artificial urticaria, purpura or contact dermatitis.
1. Artificial urticaria: the etiology is not yet clear and may be related to vasoactive mediators released by skin mast cells. If the patient’s skin is scratched, there will be a linear elevation with a red halo around it, which can be manifested as a case of redness when the skin is scratched.
2. allergic purpura: mostly due to infection, drugs and genetic factors, the patient’s typical symptoms for the skin purple petechiae, ecchymosis, pressure does not fade, so there will be a skin scratching the situation of red cholera.
3. contact dermatitis: if the patient contact with drugs and other allergens caused by allergic reactions, may appear erythema, itching and other symptoms, part of the patient in scratching the local skin, there will be a skin scratching on the situation of red cholera.
If the patient has the situation of skin scratching, it is recommended to consult a doctor in time to check and clarify the cause of the disease under the guidance of the doctor for treatment.