A patch of redness on the face may be related to urticaria, seborrheic dermatitis, allergic skin diseases and so on.
1. Urticaria: Urticaria is a limited edema that occurs as a result of a temporary increase in vascular permeability of the skin mucous membranes, which is a common skin disease. Patients in addition to a block of red on the face, accompanied by varying degrees of itching.
2. Seborrheic dermatitis: a common chronic inflammatory skin disease. Due to the high distribution of sebaceous glands in the face, coupled with the sebum secretion of the face, it is possible to suffer from seborrheic dermatitis. When the patient’s face suffers from seborrheic dermatitis, the symptoms of erythematous papules will appear, which will lead to a piece of red on the face.
3. Allergic dermatosis: When various exogenous allergens enter the body, the immune system will attack the allergens leading to an inflammatory reaction of the skin. When the patient is allergic to cosmetics such as creams and hair dyes, it may lead to redness, swelling and pimples on the face, resulting in a patch of redness on the face.
When a patient develops the symptom of a patch of redness on the face, he or she should seek medical attention for a clear examination and diagnosis.