Allergies

Allergies are what happens when the immune system overreacts to a harmless trigger in the environment. It’s a case of mistaken identity: Immune cells responsible for protecting the body against germs misidentify and react to a harmless substance. 

The allergic reaction is what happens in the body when the immune system reacts to this false threat.

The most common types of allergies are:

• Indoor and outdoor allergies 
• Skin allergies 
• Food allergies 
• Drug allergies 
• Insect allergies

Many things in the environment can cause allergies. These harmless triggers are called “allergens.” 

Allergens will be different for different people, depending on the allergy they have. These are some common allergens that cause allergies:

• Indoor and outdoor allergies: Plant pollens, mold spores, dust mites, and pet dander
• Skin allergies: Poison ivy and oak, some foods, and latex
• Food allergies: Milk, soy, eggs, wheat, peanuts, tree nuts, fish, and shellfish
• Drug allergies: Commonly, penicillin antibiotics
• Insect allergies: Bee and wasp stings, poisonous ant bites, cockroaches, and dust mites

Despite what you may have heard, these things don’t cause allergies:

• E-numbers (food additives)
• Genetically modified foods
• Fast food
• Immunizations 

To be allergic to something, you have to be sensitized to it. This means your body must have come into contact with that substance in your life and made a memory (antibodies) against it. Experts aren’t exactly sure why this happens. 

Risk factors 

Allergies can happen in anyone, but they’re more likely if you have a genetic risk for allergies (known as “atopy”).

Here are some facts about a person’s chances of inheriting allergies:

• A child whose parents don’t have allergies has roughly a 15% risk of having allergies.
• If one parent has allergies, that risk goes up to 50%.
• If both parents have allergies, the risk of allergies in the child can be as high as 80%.

Allergy symptoms can range from a mild runny nose to life-threatening anaphylaxis. Symptoms usually — but not always — affect the part of the body that comes into contact with the trigger. 

Common allergy symptoms (and their types) include: 

• Allergic rhinitis: Sneezing, congestion, and itchy and runny nose
• Asthma: Wheezing, chest tightness, breathlessness, and cough
• Allergic conjunctivitis: Itchy, red, and watery eyes
• Food allergies: Stomach pain, nausea, vomiting, and diarrhea
• Eczema: Dry, red, and cracked skin 
• Contact dermatitis: Red, itchy skin rash
• Hives: Raised, itchy skin 
• Angioedema: Swollen lips, tongue, eyes, or face

Are you not sure whether you have an allergy? Can you not figure out what’s causing your allergies? Or, are the treatments you’re taking not helping? If so, then you may need the help of an allergy specialist. 

For allergy testing to be useful, you need to have a clear link between a trigger and a symptom. In other words, you notice symptoms after coming in contact with a particular trigger. An allergy specialist can test you for that trigger with an allergen challenge. This involves pricking the skin with very small amounts of the allergen (and related allergens) to see if your skin reacts to it.

If you don’t have clear symptoms, then allergy tests usually cannot help to diagnose an allergy. Testing for allergies without any clear history of allergic reactions can give misleading results.

Once your allergy is confirmed, you’ll know what you need to avoid. If avoidance of your particular trigger isn’t possible, then your allergy specialist will be able to recommend treatments to keep your symptoms under control.

Treatments

The first and best treatment for allergies is to avoid the trigger. Next, medications can help treat symptoms. These medications can also prevent symptoms when taken before exposure to the allergen(s).

Many people with mild allergies can control their symptoms with over-the-counter (OTC) medications and by avoiding the trigger. 

But, sometimes, trigger avoidance isn’t possible, or it’s not enough to prevent symptoms. Other times, OTC medication doesn’t work well enough to treat allergy symptoms.

The main categories of allergy medications are antihistamines, corticosteroids, and decongestants. They can be taken orally. Or they can be used topically as: 

• Eye drops
• Inhalers
• Nasal sprays
• Skin creams
• Lotions
• Ointments

For food allergies, there’s a newer FDA-approved injectable medication called Xolair (omalizumab).

Antihistamines

Antihistamines block the effects of histamine, the chemical responsible for symptoms like itching, runny nose, and sneezing. These medications can prevent allergy symptoms (if taken before you come into contact with the trigger). And they can help improve the symptoms (if taken afterward). Examples include:

• Diphenhydramine (Benadryl)
• Loratadine (Claritin)
• Cetirizine (Zyrtec)
• Fexofenadine (Allegra)

Corticosteroids 

These are powerful anti-inflammatory medications, which can help with short-term treatment of irritation, redness, swelling, itching, or pain. Examples include:

• Prednisone (Deltasone) — oral
• Budesonide (Rhinocort) — nasal spray
• Hydrocortisone (Cortizone, Pandel) — cream

Decongestants

These can ease symptoms of a stuffy nose (nasal congestion) by reducing the swelling of blood vessels in your nose. You can take them alone, such as pseudoephedrine (Sudafed). Or you can take them in combination with antihistamines, such as loratadine / pseudoephedrine (Claritin-D).

Xolair

Xolair (omalizumab) is an injectable medication that’s FDA-approved for the treatment of food allergies. It’s a medication you take every 2 to 4 weeks. It lowers the risk and severity of allergic reactions due to accidental exposure to one or more foods. 

Xolair doesn’t take the place of careful allergen avoidance. And, in the case of serious allergic reactions (like anaphylaxis), it isn’t a substitute for injectable epinephrine.

Immunotherapy

Immunotherapy is a specific treatment for a small number of people with severe and persistent allergies who don’t find relief from their symptoms with other treatments. It involves taking small doses of the allergic trigger (allergen) over the course of several years. It aims to help your body get used to the allergen, so your allergy becomes milder and more manageable. The allergen can be administered either as a shot (SCIT) or as a drop (SLIT). 

If you are taking injections, these have to be given by a specialist doctor in a particular type of clinic, as there’s a small risk of a severe reaction. The drops (or tablets) can be taken at home.