Allergy Testing at Foster City Medical Center

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What is an Allergy?

An allergy is an overreaction of the immune system to an inappropriate stimulus, such as dust, pollen, grass, pet dander, mold, etc. The immune system believes it is being invaded by a parasite rather than a harmless allergen in the environment, and therefore it rallies its defenses to fight off the enemy.

Allergy Symptoms

The list of symptoms caused by allergies is longer than you might think. Primary signs of allergies include:

  • Runny or congested nose
  • Sneezing
  • Watery and itchy eyes
  • Asthma
  • Frequent ear infections
  • Sinus headaches
  • Nasal polyps
  • Conjunctivitis (eye irritation)
  • Muscle/joint pain
  • Skin rashes and eczema
  • Mental problems such as confusion, slow thinking, depression and forgetfulness
  • Respiratory effects including endless colds, chronic cough, recurrent bronchitis

Of course, there are many possible reasons for these symptoms. The only way to know if they are caused by allergies is to take an allergy test. AllerVision offers a pain-free skin test that provides answers in just 15-minutes. Any AllerVision-affiliated medical clinic will have the ability to perform the test and read the results on the spot.

Allergy Triggers

There are many items in the environment that could cause your allergies. They fall into four general categories:

  1. Animal dander — from dogs, cats and cockroaches
  2. Mold and mildew
  3. Dust mites
  4. Pollen — from trees, grass and weeds

Animal Dander (Year-round)

petbrushContrary to popular belief, it’s not animal fur that causes allergies, it’s a protein in their saliva. When animals lick themselves, the protein attaches to the fur and that’s when it becomes the problem. Then animals shed and their fur sticks in carpeting, upholstery, etc. where it can stay for months.

The same protein found in saliva is also present in animals’ urine. Therefore, gerbils, hamsters and other small caged animals could cause problems for allergy-prone individuals.

Pets aren’t the only problem. Cockroaches, common to tropical areas, also contribute large allergen particles to the space around us. Proteins in their saliva and feces become airborne easily and circulate through the air without your knowledge.

Mold and Mildew (Year-round, Especially Bad in Rainy Seasons)

petridishSimply put, mold is bad. So bad that exposure sometimes seriously affects non-allergic people. Mold reproduces when airborne spores land on wet surfaces, so any room with moisture is vulnerable, especially those that don’t dry thoroughly (like bathrooms counters, showers and bathtubs, and refrigerator drip trays). Also, plumbing leaks could cause major problems to your home and your health if they’re not fixed immediately.

Dust Mites (Year-round)

Thedustmitesse microscopic creatures can create big allergy problems. As they float through the air or reproduce in carpeting, upholstery and bedding, the protein in their droppings pollute the environment and cause perennial problems for a many allergy sufferers. Vacuuming, dusting with a damp cloth, and washing sheets regularly can help but, unfortunately, dust mites are hard to completely avoid.

Pollens (Seasonal)

pollenHave you ever rolled in the grass and then started itching? It’s allergies. The worst offenders are Bermuda, Johnson, Kentucky bluegrass, Orchard, Sweet vernal, and Timothy grasses. When lawn mowers cut them, the pollen starts flying. Keep in mind that pollen can stow away on you clothes and on your pets, so vacuum and shower frequently.

Tree pollen is another big troublemaker, and these varieties are especially to blame: sycamore, hickory, walnut, pecan, poplar, cottonwood, box elder, red maple, silver maple, willow, ash, date palm and Phoenix palm trees. Some people have cross-reactions to alder, beech, birch, oak, juniper, and cedar families as well. Removing these trees from your garden may be of little help to allergies; tree pollen can travel up to 50 miles on a strong wind.

Weeds are not only the bane of existence to gardeners, but also allergy sufferers, as they are regular pollen factories. Ragweed is the worst offender, as one plant can release 1 million grains of pollen each day. Other troublemakers are sagebrush, redroot, pigweed, lamb’s quarters, Russian thistle (tumbleweed) and English plantain.


Once you have signs and symptoms of allergies the next step is to get tested for your allergies. Here at Foster City Medical Center we do the allergy testing right in our clinic. The testing is covered by most insurance but please call your insurance company to check as each individual plan may vary as far as copay and deductible.


Frequently Asked Questions

Can I be tested if I have a skin condition or moles?

Yes. If possible, your provider will place the test on areas that are not acutely affected. If there are no unaffected areas, you will receive a blood test instead of a skin test.

Can I be tested if I have a tattoo?

Yes. The technician will place the test on areas that are not inked. He or she may use ink-free areas on your back, arms, or legs. If you are inked in all areas, you will receive a blood test instead of a skin test.

Can I stop taking allergy medications when I start drops?

You should stay on allergy medications at the start of SLIT therapy. At the first follow-up visit (about 12 weeks after treatment begins) your provider will begin to taper the medications. You may find you have already started feeling so much better by the first visit that you are no longer medication-dependent.

Do the drops work on food allergies?

They do not target food allergies and will not be effective against severe reactions to foods. However, some patients complain of itchy mouth or runny nose with certain foods. This syndrome is often not actually a food allergy but a symptom of cross-reactivity with common allergens and it will likely improve significantly with SLIT.

How does my provider measure the reaction?

Reactions are evaluated by measuring raised areas of skin with a millimeter ruler. Allergic severity is graded as follows: 2-4mm=low; 5-7=moderate; 8-10=high; 11-13=very high.

How does sublingual immunotherapy work?

Low doses of harmless allergens are placed under your tongue where they are absorbed by tiny capillaries. These allergens then attach to dendritic cells, which in turn affect your TH2 cells in ways that reduce and/or eliminate allergies and related symptoms.

How long do I stay on SLIT?

Four years. If you are unable to complete the treatment, the allergen resistance will last a few weeks or months after treatment is discontinued. You will be able to restart treatment at any time, but if several months have passed you may be advised to restart at the first stage of treatment.

How long will it take for results to develop?

Results will be available in just 15 minutes. An allergy technician will check on you every five minutes or so during that time to make sure you are okay. After 15 minutes, he or she will read the results and remove the antigens with an alcohol swab.

How long will the reaction last after testing?

If your body is allergic to certain antigens, you will get small bumps on your skin and you may feel itchiness. Both will begin to resolve as soon as the antigen is wiped away at the end of the test. Bumps usually last about an hour. In rare cases, the reaction may last longer but it is generally not uncomfortable. For the very rare cases of lasting reaction, Claritin and hydrocortisone cream help minimize discomfort.

How much does testing cost?

It is covered by most insurance plans. You will only be responsible for your regular co-pay and deductible.

How often do I need to be seen by my healthcare provider?

About every 12 weeks throughout the course of treatment. On these follow-up visits your provider will give you a quick exam, discuss your progress, and prescribe your refill. The drops should last about three months, but since a drop is not a precise measure the supply may last a bit longer or run out a bit sooner. Come in when you need to.

How often will I get retested?

Once each year. Re-testing helps you and your provider evaluate your improvement. It is important, though, to understand that the skin test is just one measure in the assessment of progress toward remission.

How safe is sublingual immunotherapy?

Drops are extremely safe, with rare, and mild, side effects. There have been no fatalities reported. SLIT has been used for over 60 years worldwide and the majority of allergy patients in Central Europe receiving immunotherapy use SLIT.

If I am on shots, can I transition to drops?

Yes! Talk to your allergy treatment provider; you’ll find the transition is quick and seamless and could start immediately!

Is sublingual immunotherapy treatment FDA approved?

The antigens in the treatment are FDA approved for use in shots. Sublingual therapy is an “off label” use. It is similar to using Albuterol in children, or giving baby aspirin to prevent heart disease. Sublingual application is clinically proven to be safer than injections and is endorsed by the World Health Organization.

Is there an age limit for testing and treatment?

No. Small children will be tested for fewer antigens than older children and adults, but the test is safe for children of any age.

Preparing Skin Test FAQs

What if I am extremely uncomfortable with reactions before 15 minutes are up?

If you have clearly positive reactions and are very uncomfortable, the technician will wipe the antigen off and read the results early.

Should we really test and treat young children?

Absolutely! Young children tolerate testing and treatment extremely well. There is a rare opportunity with young children to actually stop the well-known progression of allergies into asthma. This is the most effective path to a healthy future for children suffering from allergies!

What are the biggest advantages of SLIT?

It’s safe for children and adults; convenient because it’s administered at home and takes just two minutes per day; painless and easy; ideal for frequent travelers, who can take the drops anywhere; very cost effective.

What happens after the test?

The provider wipes the antigens off the skin with alcohol wipes. You may then receive hydrocortisone cream and/or oral Claritin if necessary to ease any lingering discomfort or itchiness. Then your provider will explain the results and discuss your options for treatment, if applicable.

What if I miss a dose of drops?

If you miss one dose, or even a few, you can pick up where you left off. If the drops are discontinued for more than one month you may be advised to restart the treatment process.

What if I take more than the regular dose?

SLIT drops are NOT medication and have no additives, so there is generally no reason to be concerned. However, it’s important to watch closely for signs of allergic reaction. Go to the emergency room (ER) immediately if you feel symptoms of severe allergic reaction.

What if my child gets a hold of the bottle and drinks it?

SLIT drops are essentially grass, weeds, pollen, etc. and are completely nontoxic; there is generally no reason to be concerned if a child consumes them. But watch closely for signs of allergic reaction and take your child to the ER if he/she develops signs of reaction.

What if my pet chews up the bottle and swallows the drops?

The ingredients of SLIT drops are part of a pet’s normal life so there is usually no reason to worry if your pet consumes them. However, if your pet shows signs of allergic reaction, take it to the vet immediately.

What should I do, or not do, before my allergy test?

  • Refrain from exercise for two hours before your test and plan to avoid exercise or strenuous activity for two hours afterward.
  • Do not take antihistamines for three days before testing. If this is not possible, contact your provider to discuss options so you can take the allergy test as scheduled.
  • Notify your provider before the test if you take beta blockers (blood pressure medication). If you are using beta blockers at the time of testing, your provider will perform a blood test instead of a skin test.
  • Alert your provider if there’s any chance you’re pregnant. He or she can test for pregnancy before the skin test. If you are pregnant, you will receive a blood test instead of a skin test.
  • Tell your provider if you are experiencing any signs of a severe allergic reaction on the day of testing (e.g. hives or difficulty breathing).
  • Inform your provider if you have been diagnosed with cancer or an immune disorder.

What should I expect during testing?

Your provider will clean your skin on your back with an alcohol swab. That will feel cool and slightly wet. He or she will warn you before the testing begins. As the first set of antigens is applied to your skin, you’ll feel small pokes from the tines of the testing device. This will last for just a few seconds and then be repeated in five areas. You can expect slight discomfort, as well as some itchiness from positive results. Try to avoid scratching while the test develops. Notify your provider if you feel symptoms other than itchiness.

When should I start to see results and how long will they last?

Within the first three months of sublingual immunotherapy (SLIT) treatment. By the time you come in for the follow up at 12 weeks you’ll likely be feeling much better and already taking less of your usual allergy medications. The length of relief varies from person to person but most patients experience significant improvement for at least 10-15 years. For some, it will be significantly longer!

Which allergies are covered by SLIT?

Your SLIT serum will be specifically formulated for you based on the allergens you are allergic to.

Why aren’t drops covered by insurance?

The FDA approved antigens for injections, not sublingual delivery. Sublingual drops are proven to be safer than injections, but SLIT is still considered an “off label” use.

Will the tines penetrate my skin?

No, the testing unit (MAST device) is pressed onto your skin; no blood is drawn. If a spot of blood does appear, the provider simply blots the area and continues the procedure.