Avoiding MSG in foods may help. MSG stimulates pain receptors.
(the NMDA receptors).

Sometimes adding Singulair to an antihistamine helps. It also helps asthma in some patients.

People with adult asthma may be low in Omega-3 fatty acids. These help build the lining of the lungs and have an anti-inflammatory action. Either eat foods to provide these, or take an oral fish oil or krill supplement. You may find your asthma goes away, like mine did.

Histamine is in many foods, and some foods are histamine releasers. This is my histamine thread:
http://neurotalk.psychcentral.com/thread161714.html

If you take blood pressure medication, and your medication is an ACE inhibitor, you might request another family of drugs.
ACE inhibitors cause a buildup of bradykinin and this biogenic amine is related to histamine. Only it does not respond to antihistamine drugs. When bradykinin builds up, you can get asthma like symptoms, and tingling in the skin. Severe reactions can be swelling and air way obstruction. I had a severe reaction to lisinopril and it lead to the discovery that I had hereditary angioedema.
It took many years to discover this, as it is not common.