It has been reported that some patients have been misdiagnosed with Contact Dermatitis, when in fact the correct diagnosis in their specific case was Urticaria (hives).
Urticaria or chronic hives are red itchy welts that result from a skin reaction that lasts for more than six weeks. Symptoms of hives include red welts called wheals anywhere on the body, these wheals can change in size, shape and appear and fade, severe itching, painful swelling of lips, eyelids and inside of throat, symptoms are triggered by heat, exercise and stress. Hives can be misdiagnosed as heat rash, contact dermatitis, rosacea, eczema, and pityriasis rosea.