Allergies- Causes, Symptoms & Types , Diagnosis & Tests,Treatment & Care

Allergies- Causes, Symptoms & Types , Diagnosis & Tests,Treatment & Care

Allergies Overview

Allergy symptoms include itchy eyes and skin, sneezing, nasal congestion, wheezing, and rash. Seasonal allergies result from grass, weed, tree pollen, or molds. Cat and dog dander allergies are common. Food allergies include peanut or milk.

What Is an Allergy?

This article explains the basics of an allergic reaction. Learn what happens when your immune system goes on high alert to something that’s usually harmless.

Who Gets Allergies?

Anyone can get them, at any age. You could develop them as a child, or you might not have any symptoms until you’re an adult.

What Causes an Allergic Reaction?

While your problem may seem to start in the nose or the eyes, allergies actually come from an immune system run wild.
Allergies and Asthma
Asthma attacks (worsening of asthma symptoms) can be triggered by allergies, which can temporarily increase the inflammation of the airways in a susceptible person.
Allergies and Sinusitis
Sinusitis is an inflammation or swelling of the tissue lining the sinuses. Allergies can trigger sinusitis.
What Happens in Anaphylaxis?
Sometimes, allergies can cause a life-threatening reaction called anaphylaxis. It’s not common, but you should be aware of what to do if it happens.
Nasal Polyps
Nasal polyps are noncancerous, teardrop-shaped growths that form in the nose or sinuses. They’re often linked to allergies or asthma.

Symptoms & Types

Learn the types of allergies including food allergies, seasonal allergies, pet allergies, and many more.

Respiratory Allergies

This is also may called also Seasonal Allergy. They are-
Spring Allergy
Summer Allergies
Winter Allergies
SYMPTOMS -of Hay Fever
runny nose
nasal congestion
watery, red, or itchy eyes
itchy throat or roof of the mouth
postnasal drip
itchy nose
sinus pressure and pain
itchy skin

Food Allergies

Is It an Allergy or an Intolerance?
Food allergies or food intolerances affect nearly everyone at some point. People often have an unpleasant reaction to something they ate and wonder if they have a food allergy.

Milk Allergy

If you suffer from a milk allergy, strictly avoiding milk and food containing milk and milk products is the only way to prevent a reaction, which can include immediate wheezing, vomiting, and hives.

Casein Allergy

If a glass of milk or slice of pizza causes swollen lips, hives, or other symptoms, you may have an allergy to casein, a protein in milk. Another milk protein associated with allergies is whey. Some people are allergic to both casein and whey.

Egg Allergy

Egg allergies are more common in children than in adults. Reactions range from mild to severe.

Wheat Allergy

It can be a challenge to avoid wheat because it’s in so many things.

Nut Allergy

If you suffer from a nut allergy, strictly avoiding nuts, including peanuts and tree nuts like cashews and walnuts, and food containing nuts is the only way to prevent a reaction.

Fish Allergy

If you’re allergic to one kind of fish, your doctor may have told you to avoid others. Here’s what to look out for.

Shellfish Allergy

If you’re allergic to one type of shellfish, you may have problems with others. Take these steps to make sure you don’t have an allergic reaction.

Sulfite Sensitivity

Sulfites are a group of sulfur-based compounds that may occur naturally or may be added to food as an enhancer and preservative. The FDA estimates that one out of 100 people is sensitive to the compounds.

Soy Allergy

If all you needed to do for a soy allergy was skip the soy sauce and tofu, life would be a breeze! But soybeans are a big part of processed foods, too.

Skin Allergies

Contact Dermatitis

Something touches your skin, and your immune system thinks it’s under attack. It overreacts and sends antibodies to help fight the invader, called an allergen. The result is a red, itchy rash where the substance landed.

Hives (Urticaria) and Angioedema

Hives, also known as urticaria, are an outbreak of swollen, pale red bumps, patches, or welts on the skin that appear suddenly — as a result of allergies, or for other reasons. In angioedema, the swelling happens under the skin, not on the surface.

Allergies to Poison Ivy, Oak, and Sumac

Poison ivy, poison oak, and poison sumac are plants that contain an irritating, oily sap called urushiol. Urushiol triggers an allergic reaction when it comes into contact with skin, resulting in an itchy rash, which can appear within hours of exposure or up to several days later.

Allergies to Insect Stings

Bee, wasp, yellow jacket, hornet, or fire ant stings are the insect stings that most often trigger allergies. Most people are not allergic to insect stings and may mistake a normal sting reaction for an allergic reaction.

Can You Be Allergic to the Sun?

Most people’s skin will burn if there is enough exposure to ultraviolet radiation. However, some people burn particularly easily or develop exaggerated skin reactions to sunlight.

Cosmetic Allergies

Some beauty products can cause skin irritation or allergic reactions. Certain ingredients used in cosmetics, such as fragrances and preservatives, can act as allergens, substances that trigger an allergic reaction.

Nickel Allergy

A nickel allergy is a skin reaction that develops after exposure to nickel or items containing the metal.

Other Allergies

Eye Allergies

Millions have different types of allergies. Most of those millions have symptoms involving their eyes.

Allergic Conjunctivitis (Pink Eye)

Conjunctivitis is one of the most common and treatable eye conditions in children and adults.

Drug Allergies

Many medications can cause side effects, and certain ones can trigger allergies.

Aspirin (Salicylate) Allergy

If you’re allergic to chemicals called salicylates, you may need to avoid certain foods, medicines, and other products.

Penicillin Allergy

Since the 1940s, penicillin has been a go-to drug to clear up infections caused by bacteria. But some people get a bad reaction from taking it.

Diagnosis & Tests


To know what you’re allergic to. Skin testing one way your doctor can check on what causes your symptoms.

These tests use extracts (a concentrated liquid form) of common allergens such as pollen, mold, dust mites, animal dander, and foods. Once those get in your skin, they could trigger a rash. Your skin will get irritated and may itch, like a mosquito bite.

That reaction is how the doctor can tell you’re allergic to something. When you have an allergy, your immune system will make antibodies and set off chemicals to fight off the trigger.

What Happens During a Skin Test?
The steps vary depending on what type of test you’re having. There are three main ways to get allergens to react with your skin.

Scratch test, also known as a puncture or prick test: First, your doctor or nurse will look at the skin on your forearm or back and clean it with alcohol. They’ll mark and label areas on your skin with a pen. Then they’ll place a drop of a potential allergen on each of those spots. Next, they’ll scratch the outer layer of your skin to let the allergen in. (It’s not a shot, and it won’t make you bleed.)

Intradermal test: After they look at and clean your skin, the doctor or nurse will inject a small amount of allergen just under your skin.

Patch test: Your doctor could put an allergen on a patch and then stick that on your arm or back.

Plan for an hour-long appointment. The pricking part of scratch and intradermal tests takes about 5 to 10 minutes. Then you’ll wait about 15 minutes to see how your skin reacts.

Patch tests take more time, and two visits to your doctor. You’ll have to wear a patch for about 48 hours in case you have a delayed reaction to the allergen.

How to Get Ready for a Test
Tell your doctor about all medicines you’re taking, including over-the-counter products. Some drugs can affect the results, so your doctor will give you a list of medicines to avoid before the test.

If you can’t stop taking a medication, your doctor or nurse may do a separate test to find out if that drug will hamper the results.

Since allergy medicines, such as OTC antihistamines, stop allergic reactions, you shouldn’t take them for a few days before your appointment. You need to let your body react to the allergens in the test.

Is It Safe?
A skin test may be mildly irritating, but most people say it doesn’t hurt. Although you’re coming into contact with things you could be allergic to, they’re very small amounts.

Whole-body reactions to allergy skin tests are rare, but let your doctor know right away if you have:

Trouble breathing
A widespread rash
Swelling on your face, lips, or mouth
Trouble swallowing
After Your Test
The doctor or nurse will clean any extracts and ink marks off your skin with alcohol. You may need to use a mild cortisone cream to ease itching.

If you get a patch test, you’ll go home with bandages on your skin. Don’t get these areas wet — no baths or swimming. When you go back to the doctor in a couple of days, he’ll take another look at your skin.

Your doctor or allergist will use the results of your test to come up with a treatment plan for you.

Treatment & Care

Allergy Medications


Antihistamines have been used for years to treat allergy symptoms. They can be taken as pills, liquid, nasal spray, or eye drops. Over-the-counter (OTC) antihistamine eye drops can relieve red itchy eyes, while nasal sprays can be used to treat the symptoms of seasonal or year-round allergies.

How Do Antihistamines Work?
When you are exposed to an allergen,it triggers your immune system.It is an exaggerated immune response. Immune system cells known as “Mast cells”release a substance called Histamine, which attaches to receptors in blood vessels, causing them to enlarge. Histamine also binds to other receptors causing redness, swelling, itching, and changes in secretions. By blocking histamine and keeping it from binding to receptors, antihistamines prevent these symptoms.

Examples of antihistamines include:

Over-the-counter:Cetirizine (Zyrtec), fexofenadine (Allegra), levocetirizine (Xyzal), and loratadine (Claritin, Alavert) are taken by mouth. Brompheniramine (Dimetapp allergy, Nasahist B), chlorpheniramine (Chlor-Trimeton), clemastine (Tavist), and diphenhydramine (Benadryl) can make you drowsy. Ketotifen (Zaditor) and naphazoline and pheniramine combination ophthalmic (OcuHist) are eye drops.
Prescription: Desloratadine (Clarinex) is a medication taken by mouth. Azelastine nasal (Astelin) is a prescription nasal antihistamine spray. Prescription antihistamine eye drops include azelastine ophthalmic (Optivar), epinastine ophthalmic (Elestat), and olopatadine ophthalmic (Patanol).

What Are the Side Effects of Antihistamines?
Antihistamines may cause drowsiness. Newer, non-sedating second- and third-generation antihistamines are available over-the-counter or by prescription.


Decongestants relieve congestion and are often prescribed along with antihistamines for allergies. They can come in nasal spray, eye drop, liquid, or pill form.

How Do Decongestants Work?
During an allergic reaction, tissues in your nose may swell in response to contact with the allergen. That swelling produces fluid and mucous. Blood vessels in the eyes can also swell, causing redness. Decongestants work by shrinking swollen nasal tissues and blood vessels, relieving the symptoms of nasal swelling, congestion, mucus secretion, and redness.

Nasal spray and eye drop decongestants should be used for only a few days at a time, because long-term use can actually make symptoms worse. Pills and liquid decongestants may be taken longer safely.

Some examples of decongestants that are available over-the-counter include:

Pseudoephedrine (Sudafed tablets or liquid)
Phenylephrine (Neo-Synephrine) and Oxymetazoline (Afrin) nasal sprays
some Visine eye drops

What Are the Side Effects of Decongestants?
Decongestants may raise blood pressure, so they typically are not recommended for people who have blood pressure problems or glaucoma. They may also cause insomnia or irritability and restrict urinary flow.

Combination Allergy Drugs

Some allergy drugs contain both an antihistamine and a decongestant to relieve multiple allergy symptoms. Other drugs have multiple effects aside from just blocking the effects of histamine, such as preventing mast cells from releasing other allergy-inducing chemicals.

Some examples of combination allergy medicines include:

Over-the-counter:cetirizine and pseudoephedrine (Zyrtec-D), fexofenadine and pseudoephedrine (Allegra-D), diphenhydramine and pseudoephedrine (Benadryl Allergy and Sinus), loratadine and pseudoephedrine (Claritin-D), and pseudoephedrine/triprolidine (Actifed) for nasal allergies; and naphazoline/pheniramine (Naphcon A) for allergic conjunctivitis
Prescription: acrivastine and pseudoephedrine (Semprex-D) for nasal allergies; azelastine/fluticasone (Dymista) combines an antihistamine with a steroid in a nasal spray for seasonal nasal allergies


Steroids, known medically as corticosteroids, can reduce inflammation associated with allergies.

Systemic steroids are available in various forms:-

Pills or liquids for serious allergies or asthma

locally acting inhalers for asthma

locally acting nasal sprays for seasonal or year-round allergies

topical creams for skin allergies

topical eye drops for allergic conjunctivitis

Some steroids include:

Prescriptions-Nasal steroids: beclomethasone (Beconase, Qnasl, Qvar), ciclesonide (Alvesco, Omnaris, Zetonna), fluticasone furoate (Veramyst), and mometasone (Nasonex)
Over-the-counter nasal steroids: budesonide (Rhinocort Allergy), fluticasone (Flonase Allergy Relief), and triamcinolone (Nasacort Allergy 24HR)

Eye drops: dexamethasone ophthalmic (Maxidex), and loteprednol opthalmic (Alrex)
Oral steroids:Deltasone, also called prednisone epocrates

What Are the Side Effects of Steroids?
Steroids have many potential side effects, especially when given orally, systemically, and for a long period of time.

Side effects of systemic steroids with short-term use include:

Weight gain
Fluid retention
High blood pressure
Potential systemic steroid side effects with long-term use include:

Growth suppression
Cataracts of the eyes
Bone thinning osteoporosis
Muscle weakness
Side effects of inhaled steroids may include cough, hoarseness, or fungal infections of the mouth.

Mast Cell Stabilizers

Mast cell stabilizers can be used to treat mild to moderate inflammation in allergy sufferers.

Mast cell stabilizers are available as eye drops for allergic conjunctivitis, and nasal sprays for nasal allergy symptoms. Like with many drugs, it may take several weeks before the full effects are felt.

How Do Mast Cell Stabilizers Work?
Mast cell stabilizers work by preventing the release of histamine from mast cells (cells that make and store histamine). Some of these drugs also have important anti-inflammatory effects, but typically they are not as effective as steroids.

Some examples of mast cell stabilizers include:

Cromolyn sodium (generic Opticrom)
Lodoxamide-tromethamine (Alomide)
Nedocromil (Alocril)
Pemirolast (Alamast).

What Are the Side Effects of Mast Cell Stabilizers?
Throat irritation, coughing or skin rashes sometimes can occur. Mast cell stabilizers in the form of eye drops may cause burning, stinging, or blurred vision when they are administered.

Leukotriene Modifiers

Leukotriene modifiers are used to treat asthma and nasal allergy symptoms. They can be prescribed along with other drugs.

How Do Leukotriene Modifiers Work?
Leukotriene modifiers block the effects of leukotrienes, chemicals produced in the body in response to an allergic reaction.

These medications are available only with a doctor’s prescription and come as pills, chewable tablets, and oral granules.

The only leukotriene modifiers that has FDA approval is Monteleukast (Singulair).

What Are the Side Effects of Leukotriene Modifiers?
Side effects of these drugs are rare but may include:

Stomach pain or stomach upset
Stuffy nose

Other Over-The-Counter Products

Some simple over-the-counter products can help with allergy symptoms. They include:

Saltwater solution, or saline, is available as a nasal spray to relieve mild congestion, loosen mucus, and prevent crusting. These sprays contain no medicine.
Artificial tears, which also contain no medicine, are available to treat itchy, watery, and red eyes.


When immunotherapy given?

If one suffer from allergies more than three months of the year.


To expose you to gradually increasing levels of the offending allergen to help your immune system build tolerance.


The FDA has approved several under-the-tongue immunotherapy tablets that can be taken at home. The prescription tablets, called Grastek, Oralair, and Ragwitek, are used for treating hay fever and  the goal is to boost a patient’s tolerance of allergy triggers. Odactra is an under the tongue medication which can relieve symptoms of allergies to dust mites.

When to Use Your Auto-Injector
An auto-injector — such as EpiPen, Twinject, or Auvi-Q — can treat extreme allergic reactions with an early, life-saving dose of epinephrine.
Living With Allergies
Non-Drug Treatments for Allergies
Natural treatments can’t replace allergy medications, but they can work alongside them. From acupuncture to supplements, here are some things that may help you breathe easier,
Allergy-Proof Your Environment
Medicines help treat allergy symptoms once they strike. But these easy steps can help you avoid having an attack no matter where you are.
Dehumidifiers for Allergies
Mold, mildew, and dust mites don’t have to make you miserable. A home dehumidifier can help you breathe again.
Dust Mite Mattress and Pillow Covers
Special mattress and pillow covers can protect against dust mites, microscopic creatures that can trigger dust allergies.
Avoiding Food Allergy Triggers
Food allergies can be serious, but you can take steps to manage them. One of the best things you can do is avoid your trigger foods.
Handing Allergies at School
Easing your child’s allergy symptoms may boost her academic and social life as well.

Leave a Reply