Understanding Allergies

 

When you don’t feel well, you want to know why–and how you can get back to feeling like your full, normal self. Sometimes those icky feelings are caused not by illnesses, but by allergies. So understanding what allergies are all about can get you on the right track.

When most people talk about having “allergies,” they mean that their nose gets stuffy, runny, or itchy. Or they say that their eyes are red and itchy and they have sneezing fits. It happens when they are around whatever they happen to be allergic to such as a cat or during certain months when the specific pollen is in the air. Doctors call that Allergic Rhinoconjunctivitis. 

This is just one of the allergic diseases you may experience.

 

The Basics Of Our Immune System And Allergies

 

Our immune system is meant to help protect us from external and internal threats. Allergies are just a part of the whole system, and every year we gain a better understanding of the interplay between immunity and allergies.

At this time there are two basic allergy types within our immune system. The first involves the antibody IgE and the second uses T cells.

IgE-Type Allergies

Immunoglobulin E (IgE) is produced by the immune system. IgE against certain specific substances sits on our mast cells all the time and is ready to react when that specific allergen is present. 

When IgE is triggered, histamine and many other immune components are released and quickly set off specific allergy symptoms depending on where the exposure is happening and the disease the patient has. The most frequent symptoms include eye, nose, and bronchial tube reactions (allergic rhinoconjunctivitis and asthma). But symptoms could also include one form of hives (urticaria). 

In the extreme, IgE-type allergies lead to the multisystem reaction of anaphylaxis. We can detect if a patient makes specific IgE allergies against a potential allergen by doing allergy prick or intradermal skin testing or by doing blood allergy testing looking for allergen specific-IgE (not IgG).

T Cell Type Allergies

A T cell-mediated allergy involves the recruitment of previously sensitized T cells into tissue that was exposed to the specific allergy molecules. The resulting symptoms then occur over the next few days. This type of delayed hypersensitivity reaction is involved with the skin disease of allergic contact dermatitis. An example is the itchy, red, oozing rash one might get with certain metal earrings. Patch testing is used to help identify what a patient is allergic to. The delayed hypersensitivity reaction can also play a role in drug allergies, farmers’ lungs, and fighting off infections.

Understanding How Allergy Types Impact You

By understanding what each type of allergy does, we can better determine whether certain symptoms can be from “an allergy.” Thus, a stuffy, runny nose might be from allergies but could also come from viral or bacterial infections, structural nasal or sinus issues, nasal polyps, vasomotor/non-allergic rhinitis, pregnancy, etc. Another example would be that constipation would not be from allergy reactions as the allergy would cause an attack that included diarrhea along with symptoms in other organ systems.

Atopy and Your Allergies

Another very important concept in allergic diseases is that of “Atopy,” or the genetic predisposition to develop allergies. When confronted with a potential threat to the immune system, some people are basically programmed to respond in a way more likely to produce allergy disease and symptoms. This allergic type is often referred to as the TH2 response. 

The person’s T cells make specific messengers, called cytokines, that direct the immune system to be more likely to develop a specific allergy, have asthma, atopic dermatitis, or allergic rhinoconjunctivitis. Family history can play some role in having this response, but many other factors play a role and include types of infections we have at specific ages and how we initially get exposed to specific allergenic foods/substances. 

Sensitivities

Many patients confuse allergies with problems that are caused by specific substances via different mechanisms. These types of reactions are often referred to broadly as “sensitivities.” When it comes to these sensitivities, the allergy antibody IgE and the T cell delayed hypersensitivity reactions are not involved, so doing the “Allergy Testing” can’t get to the cause of the problem. 

Some sensitivities can be found with specific blood testing or with biopsies. Others need to have a period of elimination and then a trial back. Examples are the immune response to gluten in Celiac disease or the lack of the enzyme lactase in Lactose Intolerance. 

Dakota Allergy & Asthma is not a referral center for sensitivities. We refer those patients to organ-specific specialists.

Some Examples Of Allergic Diseases

Nose Symptoms

Allergic Rhinoconjunctivitis is probably the most common allergy problem we all think about. The nose gets itchy and runny, stuffed up, there are sneezing fits and the lining over our eyeballs gets red and itchy when we are exposed to our allergen(s). IgE is the type of allergy reaction here, so the reaction happens soon after exposure. The skin below the nose or on the eyelids can get rubbed and thus irritated but this is minor. Headaches aren’t much of a feature. Allergic rhinoconjunctivitis can happen with asthma caused by the same allergens. 

Lung Symptoms

Asthma is the typical cause of allergic lung/bronchial tube allergic disease. There is wheeze, cough, tightness of the chest, and shortness of breath. This involves the IgE type of allergy reaction. Asthma is one of the atopic conditions, so there are triggers other than just IgE allergy. We see viral infections, cold air, irritants, etc. all playing roles.

Hypersensitivity pneumonitis is a different reaction that can involve the immune system more with T cells and perhaps IgG (a different type of antibody from IgE). Substances including mold and bacteria in farm and factory situations, proteins in bird droppings, and chemicals and metals in the industry are all known examples. Cough, shortness of breath, and at times fevers are seen.

Digestive System Symptoms

Allergic gastrointestinal symptoms are typically a part of food anaphylactic reactions. They occur quickly after ingestion of the allergen and happen essentially every time the food is consumed. Symptoms could include nausea, vomiting, abdominal pain, and diarrhea. We normally also see symptoms in other organs such as shortness of breath, cough, wheezing; rapid heartbeat, low blood pressure; or hives as components of anaphylaxis. 

If the allergen only touches the skin, we normally only see hives at the site of contact. IgE allergy is the cause of these reactions and avoidance is the fix. It must be noted that humans make many false positive allergy tests to foods, so a true food allergy diagnosis needs to document the IgE and a clear clinical reaction. IgG food testing has no role in these clinical problems.

Whole Body Symptoms—Anaphylaxis

Anaphylaxis involves the ultimate IgE reaction and results in multiple problems simultaneously. It can include hives; vomiting or diarrhea; shortness of breath, cough, wheezing, tight chest; rapid heart beating, low blood pressure, turning blue; even death. 

Anaphylaxis is a sudden condition and must be treated as an emergency. Epinephrine is the main intervention. Causes include foods, medications, and the venom of stinging insects. It rarely comes from pollens, molds, danders, or dust mites. Non-IgE mediated reactions can occur that look just like this but are caused by things such as cold temperature, exercise, or conditions such as mastocytosis.

Eye symptoms

Eye allergy can occur by both IgE and T cell reactions. They are often confused with allergy look-alikes such as dry eye syndrome and infections.

Allergic Rhinoconjunctivitis was discussed earlier and is the more common allergy issue.

Allergic contact dermatitis is very uncomfortable with itching, swelling, and (at times) oozing of the skin lesions and also the surface of the eye if the allergen gets there. Many of the fragrances, preservatives, and other ingredients in make-up, shampoos, soaps, eyedrops, etc. cause the reactions. Testing with patch testing can be helpful.

Some patients have multiple diagnoses for their “allergy eyes”.

Skin Symptoms

Allergy skin problems are common. 

We have Atopic Dermatitis patients who just have the disease as a cause. Some of them have a food co-trigger that makes it worse. Unfortunately diagnosing the correct food can be hard with all the false positive testing that happens in these patients.

Urticaria can be caused by IgE reactions. An allergen touching the skin would most often give only hives. An eaten food typically causes anaphylaxis and not just hives. Inhaled allergens could give hives but would also be causing terrible hayfever or asthma symptoms at the same time. On occasion, the bee family stings or exercises after eating a specific food could give just hives.

Finally, allergic contact dermatitis as mentioned above can lead to itchy, inflamed, oozing rashes that come on slowly and last for days or weeks. They occur anywhere the allergenic substance touches and the reactions show up 1 to 4 days later. A good history and patch testing are important in diagnosing this problem. Avoidance is needed to prevent it from happening.

Your Allergy Problems Can Get Better

 

Working together your allergy problems can get better. Making sure your symptoms are caused by an allergy is the first step to success!

Dakota Allergy & Asthma specializes in the treatment of true allergic diseases. We work predominantly with the inhaled allergy problems of allergic rhinoconjunctivitis and asthma focusing on treatment with allergy immunotherapy. 

If you need help managing your allergies, contact us today!