Defined “as your body’s reaction to a foreign substance or allergen,” an allergy, Fatima Johanna Santos-Ocampo, MD of the Section of Allergology and Immunology at Makati Medical Center says, “occurs when certain parts of an individual’s immune system are activated against substances it considers as harmful, even if it isn’t.”
Dr. Santos-Ocampo adds that allergic reactions depend on a person’s genetic makeup.
“What is considered an allergen by one person may not be an allergen to another. Once you’re exposed to these, your immune system reacts in a number of ways: some [are] minor (itchy rashes on the skin, sneezing, runny or stuffy nose, watery eyes) [and] others more life-threatening (nausea or vomiting, chest tightness, shortness of breath, loss of consciousness).”
Despite the available information, experts remain baffled by allergies.
Often discovered in childhood, they vary from person to person and some may overcome this when they get older.
Allergies are mostly genetic, or passed down from parent to child, but it doesn’t mean that the manifestations would be identical.
“Just because your father was allergic to shrimp doesn’t necessarily mean you are too. You may be allergic to another type of food or to another type of substance with a completely different type of presentation from your parent,” clarifies Dr. Santos-Ocampo.
The first step to dealing with an allergy, experts assert, is proper evaluation of the patient’s history. One thing that may be overlooked is the possibility that the patient’s symptoms may not be due to an allergy at all. An allergy specialist is trained to take a proper history to first determine whether the condition is likely an allergy or not.
Second, the information from the patient together with a thorough physical exam is key to unravel the possible culprit/s. This initial evaluation will help both the doctor and patient decide if a particular test is needed, and if so, which one will be most suitable for the patient. Most commonly, a skin prick test and intradermal test is done in the specialist’s clinic.
In the more common skin prick test, tiny drops of allergens are placed on the patient’s forearms or on the back, and each drop is introduced into the skin with a pricking device.
According to Dr. Santos-Ocampo, “the appearance of a red and itchy swelling on the part of the skin where the allergen droplet was pricked is common if you’re allergic to that allergen.” Called a wheal, this red bump manifests within 15 minutes after the skin was pricked, and usually subsides in a short while.
Meanwhile, during an intradermal test, a tiny amount of the allergen is injected into the patient’s skin. This may be recommended to determine environmental and drug allergies.
Before taking either test, the attending physician will inquire about the patient’s lifestyle, family medical history, and any medications they are currently taking.
“Over-the-counter antihistamines need to be discontinued as these may interfere with the results of the test while the decision to temporarily stop taking your prescription medicines needs to be discussed with your doctors,” Dr. Santos-Ocampo points out.
The need to do a particular method of skin test is not limited by age especially since allergies can crop up at any age. Instead, the type of test, its timing, and the interpretation of its results must be carefully discussed with one’s allergologist.
Bear in mind that a negative skin test result alone might not necessarily mean a person is absolutely not allergic to a certain substance, in the same way that a positive result alone is not enough to conclude that they are truly allergic to that substance.
“Ultimately, a doctor’s diagnosis takes into account not just a patient’s test result but his or her symptoms, medical history, and response to treatment,” explains Dr. Santos-Ocampo.
Once it’s identified what an individual is allergic to, their doctor will design a plan for them to best deal with it. It could be as simple as avoiding the specific allergen to addressing the symptoms with medication and lifestyle changes.
“If you can identify what you’re allergic to, you will be in the best position to manage the symptoms, and in a lot of instances, avoid them completely,” says Dr. Santos-Ocampo.