U.S. doctors online nowAsk doctors free
A 40-year-old member asked:

what is an allergic reaction?

7 doctor answers16 doctors weighed in
Dr. Arthur Torre
Pediatric Allergy and Asthma 51 years experience
Overreaction: An allergic reaction is an overreaction of the immune system by an allergic individual to a substance that is normally harmless. Reactions can include runny or stuffy nose (allergic rhinitis) wheezing and cough (asthma) or skin reactions like eczema or hive. ( a severe reaction can lead to difficult breathing, shock and even death in the case of anaphylaxis.).
Dr. Nanette Nuessle
Specializes in Pediatrics
A chemical reaction: An allergic reaction is when a trigger, either ingested or in the environment, causes the body to release histamine and leukotrienes. The reaction can be either local, like an insect bite or sting, or systemic (widespread throughout the body) such as what happens with ragweed.
Dr. Douglas Tzanetos
Allergy and Immunology 19 years experience
An altered reaction: The roots of "allergy" are from greek "allos" (different) and "ergos" (action). So, an allergic reaction is a "different" (from normal) reaction. The reaction occurs to an allergen. An allergen can be a pollen (ragweed), food (peanut), animal (dust mite or bee venom), or other foreign substances. Symptoms occur due to histamine and other chemicals and cause sneezing, runny nose, etc.
Dr. Linda Green
Pediatric Allergy and Asthma 45 years experience
Call your doctor: For mild symptoms i would call your doctor. If there symptoms are severe such as trouble breathing, throat closing, feeling faint you should call 911 and go to the emergency room.
Dr. Linda Green
Pediatric Allergy and Asthma 45 years experience
Allergic reaction: Not sure if this is something in the past or recent. Any severe reaction with trouble breathing, throat closing or feeling faint is an emergency and you should call 911 to be taken to the er. For past reactions the treatment will vary according to symptoms and severity. See an allergist to determine the cause and nature of the problem and the best treatment.
Dr. Justin Greiwe
A Verified Doctoranswered
A US doctor answeredLearn more
Allergic Reaction?: Not sure what you mean by allergic reaction. If you are referring to anaphylaxis then epinephrine is the treatment of choice, call 911. Allergic rhinitis is treated with OTC antihistamines, daily intranasal steroid or antihistamine sprays, saline rinses, etc. Allergy shots also an option. Avoidance of triggers is important but see an Allergist first to determine exactly what you are allergic to.
Dr. Heidi Fowler
Psychiatry 25 years experience
Allergic reaction: If you are experiencing swelling of mouth, throat, tongue or face; are wheezing or having problems breathing - then you need emergency care.

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now:

Ask doctors free
Personalized answers
Talk to a doctor
$30 per visit with

Similar questions

A 37-year-old member asked:

What's an allergic reaction to carpeting?

3 doctor answers6 doctors weighed in
Dr. Barbara Stark Baxter
Allergy and Immunology 42 years experience
Allergy to carpet: Most carpet now is made of synthetic materials. Old carpet could be made from wool, and old pads could be made from horsehair ! medium old pads might have latex or other rubber in them. The carpet itself would have to be analyzed to try to figure out an apparent allergy to it. Most apparent reactions to contact with carpet would be reactions to pet dander or dust or mold in it, or its dyes.
A 38-year-old member asked:

Allergic reaction to all cephalosporins possible?

1 doctor answer2 doctors weighed in
Dr. Steven Machtinger
Allergy and Immunology 44 years experience
Yes: Allergy to the entire class of antibiotics called cephalosporins is indeed possible. That allergy would be the common part of the molecule shared by all cephalosporins and penicillins, the beta-lactam ring.
Converse, TX
A 25-year-old female asked:

What caused my allergic reaction?

1 doctor answer1 doctor weighed in
Dr. Michael Zacharisen
Allergy and Immunology 33 years experience
Common question: An allergist is frequently asked to identify the cause of the allergic reaction. Reviewing the symptoms is a good start---cough, wheezing, runny nose, vomiting, diarrhea, rash, itching, eyes puffy, anaphylaxis. There are many triggers of allergic reactions, the most common being pollens, dust, animal dander, foods, medications, insect stings/bites, latex, metals, etc. Finding the cause is key.
A 33-year-old member asked:

How quickly does allergic reaction appear?

2 doctor answers4 doctors weighed in
Dr. Tracy Sinha
Allergy and Immunology 53 years experience
Quick: Minutes to 2 hrs.
A 34-year-old member asked:

What is causing my allergic reaction?

1 doctor answer6 doctors weighed in
Dr. Duane Gels
Allergy and Immunology 37 years experience
Why allergists exist: Finding & treating the cause of allergic reactions is the main function of an allergist. A solid understanding of the immune system is required, so that immunology goes hand in hand. Timing, prevalence of various causes, location, description, examination, associated factors, family history and finally testing enables allergists to identify the culprit, if one is present; treatment is pt-centered.

Related questions

A 34-year-old member asked:
1 doctor answer3 doctors weighed in
A 37-year-old member asked:
2 doctor answers6 doctors weighed in
A 44-year-old member asked:
1 doctor answer1 doctor weighed in
A 45-year-old member asked:
1 doctor answer1 doctor weighed in
A 63-year-old female asked:
2 doctor answers3 doctors weighed in

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now:

Ask doctors free
Personalized answers
Talk to a doctor
$30 per visit with
Last updated Jan 8, 2021

People also asked

Connect with a U.S. board-certified doctor by text or video anytime, anywhere.
$30 per visit with


Content on HealthTap (including answers) should not be used for medical advice, diagnosis, or treatment, and interactions on HealthTap do not create a doctor-patient relationship. Never disregard or delay professional medical advice in person because of anything on HealthTap. Call your doctor or 911 if you think you may have a medical emergency.