Do I Have Allergies? Causes, Symptoms, Testing and Treatment
- Victoria Wermers, RN,MSN,FNP, PMHNP
- Sep 23, 2024
- 8 min read
Updated: Aug 26
Why Do Some People Have Allergies?
Allergies occur when a person's body overreacts to various particles that enter the body through the respiratory tract, occasionally the digestive system, and, sometimes, through the skin (like a plant that has touched your skin or a bug bite). Normally, a person tolerates exposure to foreign substances, but in the case of an allergy, a person's immune system gets skewed and erroneously perceives a normal everyday substance as a threat. The body overreacts and reads the foreign substance as an "invader," which triggers the release (IgE) antibodies that go off to attack the "invaders." Antibodies then stimulate white blood cells - or mast cells - to release of histamine. Histamine increases blood flow to the area, which causes inflammation. Often, the inflammation is mild, but occasionally it can be very severe and life-threatening.
The inflammation from an allergy can show up anywhere in the body, particularly the airways, skin (rash, hives), and even the digestive system. This can cause lots of physical problems
Itchy eyes and/or nose
Watery, runny nose or congestion
Sometimes a cough and/or wheezing, sometimes even respiratory distress (reactive airway)
Occasionally, a sore throat
Sometimes a rash
And, rarely, a fever
The CDC cites the Allergy and Asthma Foundation of America, saying that more than 50 million people in the United States have allergies. They are responsible for 30,000 ER visits, 2,000 hospitalizations, and 150 deaths (1).
Why Do Some People Develop Allergies?
So why do some people react differently to various substances? There are theories about this, but science has a long way to go with research. Some allergies may be inherited but not always (interestingly, recent research suggests that a gene IL33 mutation may be related to the development of some allergies). Allergies also seem to go hand-in-hand with other autoimmune diseases like thyroid disease (hyperthyroidism/Hashimoto's) and rheumatoid arthritis. In fact, it is also interesting to note that people with hypothyroidism can actually get allergy-like sinus symptoms (2) more often than others. It seems that, for a lot of these people with allergies, the immune system has gone awry.
You can also suddenly develop allergies to something you have never had allergies to before! Several things that tend to change a person's predisposition to allergies are the following:
age, pregnancy, and a lack of early exposure.
Do I Have Allergies? Causes, Symptoms, Testing and Treatment Allergy You Have?: Which Allergy Do You Have?
Medication Allergies
Try to Figure It Out - Adequate treatment of an allergy often depends on the cause.
If you do not know what is causing your allergy symptoms. Ask yourself these questions:
Do the symptoms occur at the same time of year every year? (seasonal/environmental)
Do we have a new pet (any kind)? (Pet allergy)
Is there a certain location I go to where these occur? (environmental allergies)
Was I started on a new medication when these came on? (medication allergy, i.e., chronic cough)
Do I have other allergies?
Did I move into a new house when these began? (mold, environmental
You can also get allergy tested. There are several ways to do this (see below).
Signs and Symptoms of an Allergic Reaction
Runny, stuffy, and itchy nose
Rash, itching
Vomiting, diarrhea (food)
Tingling, itching, or swelling of the palms of the hand, the bottom of the feet, and the lips
General Treatment of Allergies
Some approaches help to treat all kinds of allergies:
Over-the-Counter
Antihistamines (common: Benadryl/diphenhydramine, Zyrtec/cetirizine, Allegra/fexofenadine, Claritin/loratadine),
Nasal steroids (Flonase/Nasonex) - some of these are also prescription
Occasionally, short-term oral decongestants (common: Sudafed), and nasal decongestants (common: Afrin 2-3 days ONLY)
Considered Natural Remedies (be careful if you have daisy or ragweed allergies, be sure you do not have cross-allergies to these herbs before you begin taking any).
Prescriptive Treatment
Steroid nasal sprays (common: Beclomethasone)
Singulair/montelukast
Steroids (common: prednisone), allergy shots, and sublingual (under the tongue)
Immunotherapy - both administered by allergy specialists
Treatment of a Serious Allergic Reaction
At this point, If you start to feel the following symptoms, you need to take action ASAP (this is approaching a VERY SERIOUS reaction - anaphylaxis). Use an EPIPEN if there is one
If available, take a couple of Benadryl or Zyrtec if you can swallow, and call for help/dial 911
Swollen tongue or throat
Difficulty breathing/wheezing (reactive airway disease)
Rapid but weak pulse
Low blood pressure
Pallor
Anxiety, confusion, or disorientation
Loss of consciousness
In the meantime, if you are with someone having a suspected anaphylactic reaction, follow these instructions from the Mayo Clinic (if you are alone, you need to call someone nearby to come assist):
Ask the person if they have allergies and if they have ever had a reaction before
Remove the allergen if possible
If an epinephrine autoinjector/EpiPen is available, press it into the person's thigh. Also - administer an antihistamine like Benadryl or Zyrtec orally, if available, if they can easily swallow
Call 9-1-1
Loosen clothing so it is not constrictive
Lay the person down if feeling faint, and elevate the legs.
Check the person's pulse and breathing and, if necessary, administer CPR or other first-aid measures.
ANYONE WITH KNOWN SIGNIFICANT ALLERGIES SHOULD HAVE AN EPIPEN TO CARRY AROUND WITH THEM- ASK A PRIMARY CARE PROVIDER TO PRESCRIBE ONE!!
Common Types of Allergy Testing - Skin Testing and Blood Testing
If your allergy symptoms become very frustrating or worsen (e.g., allergic rhinitis turning into sinusitis), you can treat them with standard methods (above) or identify the cause by gradually eliminating potential triggers from your life. Try removing one suspected allergen at a time to pinpoint what’s affecting you. If you are lucky, you might figure it out quickly, but it could take a long time.
Blood Tests: A comprehensive allergy test (ELISA is the most common test). A primary care provider can order this for you, or you can order it yourself online from a lab. You make an appointment at the lab (like a local LabCorp or Quest) to have your blood drawn for the test, and they will inform you of the test results. The blood tests screen for the ten most common allergens: Food, dust, pet dander, trees, local molds, grasses, weeds, some medications, and insect bites and stings.
Scratch Test - Here, a drop of a potential allergen is applied to the forearm, upper arm, or back. This is followed by a very small "pin prick" at the same site. If you have an allergy to the substance in the drop, a bump will arise. There are certain people who should not take this test: People on certain medications (antihistamines, steroids, some antidepressants, immunosuppressants) cause skewed results; those with recent anaphylaxis should not get this type of testing, and older people (who may not react).
The finger-prick test -As the name implies, a drop of blood is
obtained by a finger stick. Tests fewer allergens than the other blood test (ELISA)
How to check for allergies - Allergies (separately or together) can be evaluated in a few different ways:
Make an appointment directly with a lab without a doctor's order, like Quest or Labcorp
Order an at-home test from a CLIA-certified lab (HSA, FSA, card, no insurance) - they will send a testing kit to send back to them for analysis, typically with a 1-3 day turnaround time. Good if you don't have time to go to the lab. Explore our affiliate HealthLabs:
Ask your healthcare provider to order it
For more information on testing, please visit the NIH site: Prick, Patch, or blood test. A simple guide to allergy testing.
Once you know the answer, you can determine are on your way to treatment: You will have answered the original question: Do I Have Allergies? Causes, Symptoms, Testing and Treatment.
Allergies: Q&A
1. I get sick when I take certain antibiotics like Augmentin and erythromycin. Does this mean I have an allergy to them?
If it is simply an upset stomach, bloating, nausea or vomiting, or diarrhea, it is most likely an intolerance rather than an allergy. An allergy is when something ingested actually causes your immune system (IgE) to rev up, ultimately causing the signs and symptoms listed above. While a food or medication allergy can occasionally cause bloating, nausea, and vomiting (rarely a rash), those symptoms are more likely to be a problem with your digestive system (not your immune system), from something taken orally. We call this an intolerance, not an allergy. This can also happen with medication.
Various things cause intolerance. For example, a lack of certain digestive enzymes, IBS (irritable bowel syndrome), or a sensitivity of the stomach lining itself to certain chemicals. Some common culprits of intolerance include wheat/gluten, eggs, caffeine, soy, chocolate, some citrus, strawberries, lactose/dairy products, red wine, and additives such as monosodium glutamate (MSG), artificial sweeteners, and coloring. This can have a delayed onset - hours to days. Intolerance is usually limited to the GI (gastrointestinal) tract, although it may be accompanied by other things like a headache or stomach pain.
There is a fine line between allergy and intolerance sometimes. For example, some people are intolerant to certain grains, which is deemed a gluten intolerance, but others may have a gluten allergy (autoimmune-celiac disease). There are a couple of ways to find out: Get allergy tested, or you can do an elimination diet - that is, remove certain foods from your diet to see if this improves your symptoms.
2. I have allergy symptoms, but my allergy test result was negative. What's going on?
Some people have allergy symptoms, but their allergy tests are negative. I do meet these folks now and then. There are two potential explanations. The first is simply a problem of the test/analysis - A negative test result because there was a technical problem with the test or a sampling error (the sample was inadequate for one reason or another) or misinterpreted. The second cause may be that the tests are limited. They test for only specific proteins when, in fact, there are lots more that may be causing the reaction. And then there IS that possibility that it is not an allergy at all - maybe you have just used that nasal spray for too long (i.e., Afrin, which causes congestion if used too long) or that you have eaten certain foods or medications (i.e., Ibuprofen, certain blood pressure medications like beta blockers) which are causing congestion, or maybe you are getting hives from anxiety (yes, there can be a connection!).
Those are things to think about. The person doing the testing needs to investigate your symptoms, history, your family history, and so on. Whatever the case is, here is the good news: You can be treated!
One final word: Interestingly, an allergy test can be positive for a substance even when a person has never had an allergic reaction to that substance!
3. These days, it seems like I am hearing about more and more people who have allergies. Could more people be developing them?
Yes, documented allergy cases seem to be rising, especially in the case of foods (2) and allergic rhinitis (3)(congestion or runny nose). One theory, the "hygiene theory," contends that children are not exposed to certain substances as much as they used to be, so they have not been "allowed" to develop normal immunity to that substance slowly over time - things have been kept too "clean," or their parent has had them avoid certain foods. Then, suddenly, they are exposed, and the immune system goes wild. Other theories are looking at the change in the genetics of the population, an increase in pollution and other contaminants in our environment, and foods (4)(5).
