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What your mother is suffering from seems to be urticaria with angioedema
The most common cause of acute urticaria is food. Seafood, meat, poultry, egg, milk, apples, brinjal, strawberry, coloring agents etc are commonly implicated. It is subjective and any food can cause it.
Other common causes are medicines, infections, insect bites
etc. Is your mother on aspirin or any ACE inhibitors for BP or any other painkillers or tablets. It is basically a detective work to find out the trigger and you should avoid the trigger for her to get relief.
Investigations should rule out focus of infection, connective tissue
diseases like lupus, thyroid diseases and diabetes, and hereditary and acquired angioneurotic edema
IV steroids and sometimes adrenaline
might be required to bring the swelling under control. Do not worry about that, let the doctors handle it. You can think of possible triggers. Any common food prior to all 30 episodes ?
Hope this helped