The redness of the skin on the arm when it is hot may be caused by physiological factors such as high temperature; it may also be caused by diseases such as cholinergic urticaria.
1. Physiological factors: arm skin is affected by high temperature, capillary expansion, resulting in increased local blood circulation, skin redness, heat, which is a normal phenomenon. This is a normal phenomenon. After transferring to a room temperature environment, the symptoms of arm skin redness will be relieved.
2. Cholinergic urticaria: If the patient is subjected to high temperature, spicy stimulating diet, strenuous exercise and other factors of stimulation, may be induced cholinergic urticaria, resulting in patients with arm skin redness, may also be accompanied by the appearance of the surface of the skin with itching and other symptoms.
The redness of the skin on the arms when exposed to heat is considered to be normal, if accompanied by other uncomfortable symptoms, it is recommended that the patient go to the hospital to find out the cause of the disease.