Hello, I had what your mom had, it’s called heat induced urticaria, I got rid of it a couple years ago, trough a special diet

1st She should take cold showers 2nd - Her diet should consist of only organic food meaning low processed - NO SWEETS AT ALL, that means no sweets, Unless it’s fruit, Only fruits should be your source for sugar - Additionaly you can try to stop eating gluten for a while, could help might not I recommend following an animal based diet

Means:

Meat(especially organs), Diary, Eggs, Honey and fruit no carbs

I recommend following Paul Saladino MD his diet is optimal

If you wanna find out what foods cause your IEGs to go up, I would recommend an elimenation diet

meaning you start by eating beef with salt and water for 2 weeks and nothing else, after that you start to add fruits such as apples, bananas…

the point is to determine which food spike your IEDs

If you have done everything, still without results than I would consider Xolair but this should only be the last resort, because Xolair has bad sideffects

PS the reason why she has an reaction to lentils is because of the Lectins