What Causes Headache After Taking Antihistamine Medication?

Posted on Tue, 10 Nov 2015

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Tue, 10 Nov 2015 Answered on

Tue, 8 Dec 2015 Last reviewed on

Question : Five weeks ago I had developed quarter size red itchy blotches on my skin. Four weeks ago I began getting head aches which started becoming severe head aches. When the head aches started becoming severe it started causing nausea and vomiting. One day when my head ache was most severe I believe I blacked out for a short time and vomited I went to the ER and they ruled out aneurism. Now I'm dealing with hives and itching over my entire body. My question is, could it be that all of this is due to an overreaction by my immune system pumping out too much histamine since this is the first time I have had an allergic reaction? And since I have been taking anti histamines I haven't been getting sever head aches. I still have hives but recently up the dosage of Benadryl and am taking steroids.
I want to know if all of my symptoms are due to an immune system response from the allergic reaction (not what my allergic reaction is) and if the allergic reactions go hand in hand.

Answered by Dr. Sassen S Kwasa (3 hours later)

Brief Answer:
Yes you symptoms are related to the allergic reaction that you had

Detailed Answer:
Welcome to HCM.com. Please note that the histamine release will cause headaches by vasodilitaory effects, at the same time you blacked out due to low blood going to your head, what we call hypotension due to anaphylaxis/same response when one is in septic shock. So these symptoms should and will get better with treatment, don't forget to hydrate and this is the best way to augment effect blood volume. I hope this helps and good luck.

Above answer was peer-reviewed by : Dr. Raju A.T