"Chronic hives are also associated with thyroid disease - hypothyroidism and hyperthyroidism. An infection with the yeast, Candida albicans, is also associated with chronic hives. All of these conditions should be ruled out. Skin testing is of variable benefit since people with hives tend to react positively to most agents tested for."
My son had hives on and off until he started thyroid medication for low thyroid (hypothyroid) and the biofilm protocol for yeast. His TSH wasn't high on the typical TSH test, but Dr. Kellman did the TRH stimulation test, an older test. Yeast overgrowth also interferes with thyroid receptors, according to Dr. Morton Teich, so the conditions are not unrelated. Anecdotally, a mother I know, from India, told me that in India, if the mother is hypothyroid and her child displays symptoms of low thyroid they often prescribe a low dosage of thyroid medication for the child. After hearing this from my friend, I looked into whether my children were suffering from a thyroid problem.