How are you? A physical allergy may have triggers or stimulus such as cold, sunlight, heat or other stimuli that cause sweating, vibration and even physical pressure. It is important that you avoid the stimulus. This is said to be due to changes in a protein in the skin. The symptoms such as itching and rashes or hives tend to develop within minutes of exposure to the physical stimulus. Over-the-counter antihistamine medications may help relieve the itching.If it persists, have this checked by your doctor for proper evaluation. Take care and do keep us posted.