Corticosteroids – cortisone and hydrocortisone – are hormones produced naturally in the body by the adrenal cortex (part of the adrenal glands, which are located on top of each kidney). It's not a steroid deficiency, though, that prompts the use of steroids (usually synthetic) to treat allergy.

These steroids are potent anti inflammatory agents, and are therefore useful in soothing the sensitive, hyperirritable airways of asthma. But steroids present some real problems. As you can see from Allergy Drugs and Their Side Effects, steroids carry a higher risk of adverse effects than any other drug.

It's important that they be used only when absolutely necessary, in a small a dose as possible, for as short a time as possible – one to five days. The main problem is that while a person receives synthetic hormones, the adrenal glands automatically slow or shut down production of natural steroids – and in some people, don't resume production until several months after all forms of corticosteroids (oral, inhaled, topical) are discontinued.

With natural steroids cut off long periods, the body loses it's power to manufacture infection fighting eosinophils and lymphocytes in the blood, depressing immunity to bacteria and viruses. Steroid therapy also thwarts the growth of children by slowing formation of collagen, a basic structural material of bone.

Those side effects – depressed immune response and impaired collagen formation – have responded to high doses of vitamin C. Hiram C. Polk, Jr., M.D., and another researchers at the University of Louisville School of Medicine found that vitamin C reversed cortisone’s effect on the immune response and restored the ability of white blood cells to kill bacteria (Journal of Surgical Research, February, 1977).

And in Athens, Greece, doctors found that vitamin C normalized the rate of collagen formation in children on steroid therapy (Archives of Disease in Childhood, May, 1974). Besides taking vitamin C, other measures can help allergy, sufferers against the effects of steroids.