Bill, who is my son and 24 years old woke up with hives on both hip areas and 2 very large round hives on the back of each thigh. (one on each leg) Went to Walgreens and bought Benadryl . He does have alot of allergies and asthma. He took 2 benadryl and is taking a cool shower. We bought Benadryl cream  but after reading the package decided it was too much medication of Diphenhydramine.
Hello, Your son Bill is suffering from an acute urticaria eruption and can happen if he is allergic to foods (which is usually easy to figure out), Chat Doctor. That he woke up with the hives would suggest a spontaneous episode, but ensure he had not taken any meds the night before. Long acting antihistamines like Fexofenadine 180\u00a0mg and/or Cetirizine 10\u00a0mg will be required for 2 weeks to ensure a complete resolution. If this recurs, do get allergy testing if there is a clear trigger or thyroid function tests. Best Wishes.