What Causes Urticaria?

Posted on Thu, 17 Apr 2014

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

Thu, 17 Apr 2014 Answered on

Wed, 7 May 2014 Last reviewed on

Question : I have on going urticaria for 4 months (started on my hands only for two months, then legs, upper body, face and recently mostly on my arms hands and wrists). My doctor told me it must be from inhaled allergen because ai decelopped chest tightness, breathing problem, headache and nosea with urticaria at work. Prick test with an Allergist revealed Dust mites, cats, dogs, cockloaches, weed and tree pollen. Patch testing at Dermatologist was performed for house hold chemicals and glove additives and cosmetics, they were negative with a couple of doubtful reactions. I was recently diagnosed as Atopy and had numerous skin tissue eosinophils with higly elevated igE. I am taking Allegra/Tagamet for my urticaria treatment. My dermatologist recently suggested to go back to Allergist to identify the cause of my urticaria because he didn't test food and latex. Do I need ImmunoCAP® Specific IgE Blood Test or RAST test? What allergens Doctor can identify from the testing above? Your answer will be greately appreciated. XXXX

Answered by Dr. Dr. Rahul Kumar (4 hours later)

Brief Answer: RAST is the best test available now Detailed Answer: Hello Thanks for the query. Urticaria is an allergic reaction and anything in this world can cause urticaria. RAST is the best test available now to identify the causative allergen. However it will be better if you can identify the allergen yourself by noticing your daily activity. Try to take a bland diet like only bread and potatoes followed by slow introduction of a new food daily and notice when you are developing urticaria. This is the best method to identify the causative agent. Let me know if you have any other doubts. Thank you

Above answer was peer-reviewed by : Dr. Shanthi.E

Follow up: Dr. Dr. Rahul Kumar (16 hours later)

Thank you Dr Rahul! I will seek the testing. Do you think RAST is better than ImmuniCap? Or both are the same? I feel that I have more of dust mite and other environmental chemical allergy rather than food because I read an medical literature saying Urticaria from actual food itself is only 1% of populatiom in all urticaria patients, I also read the food containing histamine would aggrevater of urticarica. I will still try to eat one food then add more to see if my Urticaria is better or worse like you said. It was a great advice. Again, I want to know the differnce between RAST and Immuno-Cap and which one is better to evaluate the true allergen in my cas? Well, I don't want to give up my favorite food all at once just yet. Ha hae

Answered by Dr. Dr. Rahul Kumar (32 hours later)

Brief Answer: go for RAST Detailed Answer: Hello RAST is the best available test. Just do this little exercise of introducing one food at a time, you might find some allergen in that. You are correct food allergy is less common but it is one thing which can easily be controlled. Thank you

Above answer was peer-reviewed by : Dr. Vinay Bhardwaj