I consider antihistamines toxic drugs with adverse effects on consciousness, and I would go to great lengths to avoid them. In the past few years new antihistamines have appeared that are not absorbed into the brain. These products do not cause drowsiness and depression, but they do not work for everyone, and they are expensive. An objection to all antihistamines, whether they enter the brain or not, is the suppressive nature of their action. They do not change the allergic process, merely block its expression.
Suppressive treatment can perpetuate disease by frustrating it.
All allergies have the potential to disappear if you make changes in your lifestyle and mental state. Regular use of suppressive therapies reduces that possibility. Steroid drugs are even more powerful suppressors of allergic reactions than antihistamines. The drugs in them are not supposed to be easily absorbed into the system. These can be strikingly effective in relieving symptoms, but some of the steroids are bound to get into the rest of the body, and these hormones weaken our immune systems.