Red pimples appear when the body itches

Itching of the body, a scratch shows red pimples, which is artificial urticaria, a special type of urticaria, also known as skin scratch sign, due to the patient's physiological response to weak external mechanical stimulation enhanced, scratching the skin, mast cells will release histamine bioactive substances, causing skin capillary dilation, permeability increased, so that plasma, tissue fluid penetration into the dermis caused, The patient will show a well-defined localized edema or wheal within a few seconds to minutes, surrounded by a flush, accompanied by increased itching, and the patient's desire to scratch. For treatment, it is recommended that the patient regularly take H2 antihistamines such as cimetidine, ranitidine, famotidine, etc.