What is inhalant allergy testing?

Inhalant allergies are reactions to things you breathe in like pollens, molds, dust and animal dander. There are two ways to test for inhalant allergies: skin testing and blood testing. Skin testing is more accurate, so blood testing is used only for special situations.

There are some medications that interfere with the results of skin testing or make skin testing less safe. Your doctor may have you stop taking certain medication five to seven days before testing. While it’s usually safe to stop your antihistamine allergy medication on your own, do not stop taking any medications for heart, blood pressure or eye problems without specific approval from the doctor who prescribed you these medications.

What should you expect before, during and after your test?

There are two methods of performing inhalant allergy skin testing:

• Skin prick testing
• Intradermal testing

The skin prick testing device has small plastic prongs that penetrate the superficial layers of your skin. Children as young as five years old can easily tolerate this type of testing. For most patients, this test provides sufficient information. Occasionally, if these test results are ambiguous, your doctor will proceed with intradermal testing. This test places antigens at a slightly deeper layer of the skin, forming little bleb, similar to a tuberculosis skin test.

For blood testing, the physician decides which allergens to test you for based on your medical history. You’ll have several small tubes of blood drawn in the lab. The blood is then tested against each of these potential allergens.

The advantage of blood testing is that it only takes a few minutes in the lab, and since no allergens are placed on the skin, there’s absolutely no risk of a negative reaction to the test. This type of testing is particularly appropriate for people with asthma that is not well-controlled, those who are pregnant, who have rare skin conditions that do not allow them to stop taking antihistamine medication for five days prior to skin testing, or who are taking a high blood pressure medication, or certain types of eye drops.

What is skin contact allergy testing?

Skin contact allergy testing, or patch testing, is a way of diagnosing whether there are substances in your environment that react with your skin to cause allergy symptoms ranging from a rash or hives to chest tightness or difficulty breathing.

Possible allergens include virtually anything your skin comes into contact with:

• Hair and skin care products
• Cleaning and laundry products
• Jewelry
• Clothing
• Glues
• Topical medications

If your history suggests a possible skin contact sensitivity, you may be advised to have patch testing.

What should you expect before, during and after your test?

Patch testing is different from allergy skin testing for inhalants. With inhalant testing, the test substances are placed on the skin, and a reaction occurs or doesn’t occur within 20 minutes. The allergens in patch testing can cause a reaction over a 12-to 24-hour period or more, so the test substances have to be in contact with the skin longer. To make this practical, here’s how the test is performed:

• Test panels of common allergens are attached to medical adhesive paper, with several in each group.
• The panels are placed on the back, between the shoulder blades. They are flat and comfortable to sleep on.
• There are left in place for two to three days, and then removed.
• The first reading is then performed, and a second reading is performed another two to four days later.

Why two readings?

At the time of the first reading, you will have had adhesive paper on your skin for more than 24 hours. The paper alone can irritate the skin, even if there were no allergens present. Sometimes tests that look positive at the first reading calm down and disappear before the second reading. If this occurs, the response was probably inflammation and not true allergy.

Allergy medications are often the first defense against allergic symptoms that cause you problems.

Oral Antihistamines

First-generation antihistamines are very effective, but have the use-limiting side effect of making many people very drowsy. Most first-generation antihistamines are available without a prescription. Newer second-generation antihistamines have been formulated to avoid the drowsiness and are available over the counter. Nasal sprays: Sometimes it’s better to use the antihistamine topically, limiting most of its action to the nasal area where symptoms are occurring.

Eye Drops

There are two basic types of over-the-counter allergy eye drops. The first is a combination of antihistamine and decongestant. The antihistamine component is effective at managing itching. The decongestant is effective in decreasing redness of the eye, however there’s a rebound effect if used long-term. That is, when drops are stopped, the redness can be worse than before using the medication. Therefore, the drops should only be used for a maximum of three days at a time.

The second type of over-the-counter allergy eye drop contains only one medication, ketotifen. This is an antihistamine and mast cell stabilizer. Both of these actions help minimize allergy eye symptoms.

Leukotriene Modifiers

Leukotrienes are another of the body’s chemical messengers of allergy. Unlike histamine, however, it’s more active in the late response to an allergic stimulus (occurring two to four hours after exposure to allergens). The main leukotriene modifier used in the United States today is Singulair.

Nasal Steroid Sprays

Nasal steroids are one of the cornerstones of allergy treatment. The nice thing about the sprays is that since they’re used in the nose, there is minimal absorption by or effect on the rest of the body. The most common side effect of nasal steroids is irritation or mild bleeding of the septum (dividing wall between the two halves of the nose). Other common side effects of using steroid nasal sprays are dryness inside the nose or headache. Two more serious, but rare, side effects of nasal steroid use are a thrush (yeast) infection in the back of the nose or a septal perforation (hole between the two sides of the nose). There is some evidence that nasal steroid sprays may increase pressure in the eye. If you have glaucoma and are using a nasal steroid spray, it’s important to have your intraocular pressure checked regularly.

Decongestants

Decongestants, available as oral or topical medications, help with a stuffy nose. They’re highly effective, but have some major side effects and disadvantages. Always read labels carefully, and understand what medicines you are taking. Decongestants may not be right for you if you have high blood pressure, prostate enlargement, glaucoma, rapid heart beat or sleep problems. Be sure to ask your physician if decongestants are safe for you to take.

A mild food allergy reaction can be treated with an over-the-counter oral antihistamine. Liquid antihistamines get into the bloodstream faster than pills or capsules.

The only treatment of immediate-type food allergies is lifelong avoidance. Avoiding obvious forms of the food is pretty easy. But hidden forms of the allergic substances are often hard to avoid. For example, if you’re allergic to milk you won’t drink it, or eat ice cream or cheese. But whey is a milk protein, and is found in many prepared foods such as bread.

Another concern is the risk of accidental exposure: the restaurant waiter who doesn't take seriously your request for “nothing containing shrimp,” or the classmate who brings cookies to your child's classroom, forgetting the treats contain peanuts.

In some cases, difficulty swallowing could be a sign of a condition known as eosinophilic esophagitis. This allergic reaction is triggered by food and environmental allergens and causes white blood cells in the throat to become inflamed. Treatment of eosinophilic esophagitis varies depending on the source of the allergic reaction. Your doctor may eliminate specific foods from your diet or prescribe glucocorticosteroids to control inflammation.

For more serious food allergy reactions, such as chest tightness or trouble breathing, feeling like your throat is closing, lip and tongue swelling, or severe generalized hives, you should carry self-injectable epinephrine that you or a friend or family member can inject into your thigh.

Keep in mind that using self-injectable epinephrine is just a temporary measure and the symptoms will return. Always call 911 or head to the nearest emergency room immediately for complete treatment.

How does immunotherapy work?

The theory behind allergy immunotherapy is helping the body’s immune system build a tolerance to the allergens it currently reacts to. This is done by starting with very small amounts of these allergens taken as shots or drops, and gradually building up to a target dose we know is effective. This takes between one to five months to get to the target dose, depending on the form of immunotherapy you are using, and how your body tolerates it.

Once you reach the target dose, you continue at that dose for three to five years, with important changes taking place in your immune system over that entire time. When you finish with immunotherapy, most people have a three or more years of sustained relief.

Why use immunotherapy?

The other mainstays of allergy treatment – avoiding allergens or using medicines to control symptoms – only make temporary changes. Immunotherapy makes permanent changes in your immune system, helping you develop tolerance to the allergens that cause reactions. Additionally, immunotherapy can decrease the rate at which you develop future allergic sensitivities, and can improve or prevent asthma in allergic children.

What's it like to get allergy shots or drops?

Immunotherapy can be delivered as weekly allergy shorts (injection or subcutaneous immunotherapy, also called SCIT) or daily under-the-tongue treatments (sublingual immunotherapy, or SLIT).

Allergy Shots

Allergy shots (subcutaneous immunotherapy or SCIT). Your allergy injections are specifically formulated for your allergies. No one else has an allergy vaccine exactly the same as yours.

Allergy shots are given once a week. While climbing to the target dose, these shots must be delivered in the physician’s office, or the office of another physician with the expertise and equipment to treat an allergic reaction. This is because there’s a greater, though still small, chance of an allergic reaction occurring when the dose is being increased.

After you reach your target dose, you or a family member can administer the shots at home. You must agree to stringent safety measures if you choose this option: you must always have auto-injectable epinephrine and liquid antihistamine with you, always have another adult with you for 20 minutes after the shot, and always have a land line or cell phone capable of reaching emergency responders.

Most reactions are just small red areas on the arm. If the redness is any greater than the size of a dime after an injection, or if you have any general symptoms like hives, chest tightness or shortness of breath, call your physician or 911 immediately.

Allergy Drops

Allergy drops (Sublingual immunotherapy, or SLIT). Sublingual (under-the-tongue) immunotherapy (SLIT) can be used instead of shots. SLIT has been used extensively in Europe, Asia and Australia for the last 30 years, but only recently in the United States. It’s been shown to be highly effective in treating allergies.

As with allergy shots, your SLIT vaccine is mixed specifically for you, with only the allergens to which you are sensitive. You would receive your very first dose at the office, and thereafter take your daily drops (even during your escalation) at home. This is because SLIT is even safer than allergy shots. When you are at your target dose, you’ll be using your allergy drop vial to deliver three squirts under the tongue. You’ll hold these there for two minutes then swallow the dose.

Some people experience mild tingling or itching in the mouth with SLIT. The chances of a serious reaction are very small.

Dust mites are microscopic arthropods (bugs) that live on shed human skin flakes. Anywhere humans are, they are. Allergy to dust mites is fairly common. Removing as many of these allergy-triggering dust mites as possible from your environment will make your symptoms better. The first focus should be on making your bedroom and any other area you spend significant amounts of time in as dust mite-free as possible.

Fortunately, there are many inexpensive strategies that will minimize your exposure to dust mites. Those include:

• Washing bed linens at least weekly in hot water (130-140 degrees Fahrenheit) or using laundry additives during washing can help kill or reduce dust mites. Putting a comforter in a dryer for 20-30 minutes will also decrease the amount of dust mites present.
• Dust mites love to inhabit carpeting. Ordinary vacuuming is not particularly effective in removing dust mites. Special HEPA vacuums are available that are more effective in removing dust mites.

Food allergies generally come in two forms. Some allergies show symptoms immediately, such as an allergy to peanuts or shrimp. Other allergies take longer for symptoms to develop, or may only develop if a certain food is heavily consumed.

Other types of food reactions include oral-allergy syndrome, celiac disease and food intolerance:

• Oral-allergy syndrome: Those suffering from oral-allergy syndrome may suffer from tingling or itching of the lips, mouth or throat after eating certain foods. Oral-allergy syndrome occurs when a person is allergic to certain pollen and their body is fooled into thinking the pollen is present in their food, creating an allergic reaction.
• Celiac disease: Individuals suffering from celiac disease, also known as gluten-sensitive enteropathy, experience a series of gastrointestinal issues when ingesting gluten, which is found in wheat, rye and barley. Symptoms include diarrhea, gas and abdominal cramping.
• Food intolerance: These are food reactions that aren't caused by the immune system at all, so they aren't allergies. They may be enzyme deficiencies, direct effects of the food on histamine (compound released by cells) or even food poisoning. An example of food intolerance is lactose intolerance.

There are some foods that contain a naturally occurring chemical similar to the body's main chemical messenger of allergy – histamine – or chemicals that can cause the body to release histamine directly without any participation by the immune system. These can cause symptoms in very sensitive individuals. Foods that may do this include strawberries and tomatoes.

What are the symptoms of stinging insect allergy?
A sting can often result in a very large local reaction (swelling that extends beyond the sting site). These reactions can be bothersome, but do not necessarily mean that you have venom allergy. Some patients have venom allergy, which can cause more severe reactions in sites distant from the sting. These reactions may include hives, itching, or swelling in areas other than the insect sting, abdominal symptoms (such as vomiting or cramping), difficulty breathing, lightheadedness or passing out, and anaphylaxis (life-threatening allergic reaction). 

What stinging insects cause venom allergy?
Venom allergy is usually caused by reactions to honey bee, wasp, yellow jackets, hornets and fire ants. 

How does Ohio State diagnose venom allergy?
Our board-certified allergists will take a detailed history about your reaction and discuss allergy testing options, which may include skin testing and/or blood testing.

How does Ohio State treat venom allergy?
If you have venom allergy, we recommend that you carry auto-injectable epinephrine at all times, especially in cases where you may encounter an insect sting. For most people, the best long term treatment for venom allergy is immunotherapy, or allergy shots. This treatment can prevent life-threatening allergic reactions to venom stings. Once the specific insect venom you’re allergic to is identified, a customized vaccine is mixed for you. Treatment with venom immunotherapy is generally recommended for three to five years, or longer in some cases. 

Molds are found everywhere, indoors and out. There is no way to completely avoid them, but if you are allergic to molds, your symptoms will be better if you minimize your exposure. Mold grows well in damp conditions, so the places indoors that may be harboring mold include kitchens, bathrooms, basements and laundry areas. Clean these areas with a bleach-containing cleaner. It is also advised to monitor the humidity inside your house, ideally keeping it at or below 40 percent. Dehumidifier units can help reduce mold count in areas that tend to be damp. When outside, avoid gardening and lawn mowing. In addition, when conditions are rainy, damp or foggy, mold counts tend to increase.

People who are allergic to animals react to saliva, skin flakes (dander), urine or feathers. Avoiding the animal(s) causing the problem is the simplest solution, but isn't always possible. If your work requires being around animals, or if an animal is a beloved family member, there are some actions you can take to minimize the symptoms you develop around them. Ohio State is a pet-friendly allergy practice and will work with patients to find a solution to your reactions to enable you to keep your pets.

The most important step is making at least one area in your home a dedicated animal-free zone. The bedroom is a great choice for this area, which will permit you to rest undisturbed by allergy symptoms. Brushing and washing your pet regularly can help reduce the amount of dander exposure. In addition, immunotherapy is available to help your body build a tolerance to the allergens it reacts to.

Most plants pollinate in the early morning, so allergy symptoms may be more prevalent then. Plan outdoor activities for later in the day to avoid peak pollen times. Pollen counts may also be lower during rainy days, as pollen is washed from the air. In contrast, windy days may increase your symptoms. After spending time outdoors, showering and changing clothes can help you prevent symptoms. In addition, wiping your pet with a damp cloth when they return from outside can help remove the pollen from their fur.