Allergic to Antihistamines—really!

 

This is from Gary Stadtmauer, MD’s blog. 

How many times have we heard patients say they are “allergic” to drugs like antihistamines and corticosteroids?  Hypersenstivities to medications used to treat allergic diseases are fortunately uncommon. 

This is Dr. Stadtmauer’s experience with “allergy” to Benadryl….check the references below–it’s legit! 

“I have seen a couple of cases of drug exanthem from antihistamines but never immediate hypersensitivity…until now.  I recently saw a young woman who has had recurrent urticaria/angioedema of immediate onset due to Benadryl.  She had no associated symptoms.  Scratch testing to Benadryl 5mg/ml was negative but ID was positive at 0.5 mg/ml (W/F of 4/10) and 5 mg/ml (W/F o 5/10).  See image below.

One could question whether this is an IgE-mediated event.  Perhaps it is or perhaps in the occasional patient the antihistamine acts as an agonist, binding to the receptor instead of blocking it thereby triggering histamine release.  Anaphylactic shock caused by a challenge with 12.5 mg oral diphenhydramine has been reported and the authors of this case suggest the mechanism was IgE-mediated.

Benadryl Skin TestSo what?  Never say never when a patient comes in with a bizarre drug allergy or states that are allergic to Benadryl….you might be surprised!

Citations re:  Antihistamine Allergy
1. Barranco P, López-Serrano MC, Moreno-Ancillo A. Anaphylactic
reaction due to diphenhydramine. Allergy. 1998; 53: 814.
2. Weidinger S, Mempel M, Ollert M, Elser I, Rakoski J, Köhn FM,
Ring J. Anaphylaxis to mizolastine. J Allergy Clin Immunol.
2004; 114:979-81.
3. Rodríguez del Río P, González-Gutierrez ML, Sánchez-López J,
Núñez-Acevedo B, Bartolomé Álvarez JM, Martínez-Cócera C.
Urticaria caused by antihistamines: report of 5 cases. J Investig
Allergol Clin Immunol. 2009; 19 (4): 317-20.
4. Gonzalo-Garijo MA, Jiménez-Ferrera G, Bobadilla-González P,
Cordobés-Durán C. Hypersensitivity reaction to mizolastine:
study of cross reactions. J Investig Allergol Clin Immunol. 2006;
16 (6): 391-3.
5. Demoly P, Messaad D, Benahmed S, Sahla H, Bousquet J.
Hypersensitivity to H1-antihistamines. Allergy. 2000; 55: 679-80.
6. Aberer W, Bircher A, Romano A, Blanca M, Campi P, Fernandez
J, Brockow K, Pichler WJ, Demoly P for EDNA and the EAACI
interest group on drug hypersentitivity. Drug provocation
testing in the diagnosis of drug hypersensitivity reactions:
general considerations. Allergy. 2003; 58: 854-63.

Advertisements

5 thoughts on “Allergic to Antihistamines—really!

    1. I believe I’ve just discovered today that I, too, am allergic to antihistamines. I was having so many symptoms which include, stringy eye goop, difficulty breathing, stuffed up nose and sinuses were a problem, after a while I developed an issue with my joints all feeling like they constantly needed to be popped or cracked… even my throat began to swell and close up on a couple occasions. This is when I began taking Benadryl. I had thought maybe I was allergic to cigarettes. I was already on hydroxyzine which was prescribed to me to be used as a sedative. I found that just one benadryl didn’t help me at all and as I read on the instructions on the box, you can take 2 every six hours also. So I tried that. It worked at first, but then I got all the symptoms back even worse than before. So I stopped taking the benadryl, yet continued to have symptoms. I made an appointment with the allergist for Feb. 29th, 2016 and was told I must go off all antihistamines for 5 days prior to the appointment which includes my hydroxyzine. Today is the 24th, the first day without any antihistamines at all, and guess what? I have zero symptoms today! It’s all very strange to me, and I am going to keep my appointment with the allergist to get to the bottom of what started this in the first place!

      1. Lori,
        Patients all have different responses to antihistamines, and I’m glad that yours improved. Often, patients who stop their antihistamines are miserable for a week because their allergy symptoms really increase. Have a good spring. lw

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s