Medicine not working?

I've had hives for the past two years. The first time I got them, I was prescribed Zyrtec to get rid of the hives. It's worked wonderfully, until about two days ago. I took the medicine, but I started getting hives on my bottom. It spread all over my body by the next day and I was really worried because the medicine did not seem to have worked at all. I took Zyrtec again this morning, and it helped a little, but I'm still getting hives. I was wondering if this is just a flare up and will it go away soon if I continue taking the medicine? I'm really worried right now and am in a lot of stress over this. Please help me

[Bhupinder Kaur, MD]

Hello,

Many cases of hives are "idiopathic," meaning no cause is known. Others may be triggered by viral infections or medications.

The mainstay of treatment of hives is antihistamine which may be necessary for prolonged periods (in excess of 6 weeks). Double conventional doses of these non-sedating antihistamines such as Cetirizine (Zyrtec), Loratadine (Claritin), Acrivastine and Fexofenadine may be needed to get symptom relief. Sedating antihistamines such as Chlorphenamine or Hydroxyzine are used at night to get urticaria control. Short courses of oral cortisone or steroids are taken for short periods (one to three days) to settle more severe symptoms.  You can also apply 1%hydrocortisone cream on the effected area.
You may take Vitamin C along with the prescribed treatment. Vitamin C is a general anti-allergy supplement. It helps stabilize mast cells so they are less likely to release histamine.

If the hives don’t go after 6 wks of treatment also, then it can be a case of chronic urticaria which needs further evaluation as it may be due to auto antibodies.

If the symptoms persist, then you can consult an immunologist. He may start with immunotherapy(allergy shots)
Take care and pls do keep us posted on how you are doing.