Hi, Definitely, your son may have Sun allergy due to exposure to Sun. The resulting symptoms of a Sun allergy look like a widespread red rash. The rash can develop small bumps which look like hives. These rashes are usually very itchy and these develop on exposed parts like head, neck and face. A toddler may have abnormal reaction to exposure to Sun, it is known as photosensitivity. Most of the sun rashes resolve on its own. Over the counter, aloe vera or anti-itch ointment can be helpful. Cool compresses or cool bath may provide relief from itching. More home remedies like oatmeal bath or applying coconut oil, tea tree oil or apple cider vinegar may be helpful. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Satnarain Bansal, General & Family Physician