Hello, Hives (urticeria) acute rash lasts less than 6 weeks, you symptom just 1 week so it is acute hives. It cause by allergic reaction to certain foods or medications. Hives occurs when high levels of histamine and other chemical messengers are released into the skin and elsewhere in the body. There are two types of receptors. The first type of receptor is a histamine type one receptor and there s a second types of histamine receptor called histamine type two which is mainly wound in the stomach. However, these same type two receptors can also be found in the skin. Your heartburn can cause from your allergic reaction including hives. Benadryl alone seem to be not enough for treatment. For my practice I would like to prescribe antihistamine like cetirizine, or loratidine first. They wont make you sleepy. They usually only cause mild side effects, like dry mouth and eyes. Combination with benadryl is short acting taken at night time if your hives are severe because it can make you drowsy. And add H2 blocker is type of antihistamine such as famotidine or ranitidine can use for ease heartburn and for your hives, they narrow blood vessels. That calms redness. If those drug doesn t help, your doctor might prescribe a corticosteroid. These drugs calm the immune system, that can make your hives less severe. At home you should avoid irritants such as perfumes, fragranced soaps or moisturizer and stay out of the sun. You can use a cold compress to reduce itchily and inflammation. Go to visit your doctor for the option of treatment. If your symptom worse such as difficult to breathe, nausea, vomiting, severe heartburn, blurred vision, headache, dizziness, skin rash swelling go to see your doctor as soon as possible. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Heang Chan Raksmey, General & Family Physician