An allergist will review your symptoms, run targeted tests to identify exactly what’s triggering your reactions, and build a treatment plan to manage or reduce your allergies. A typical first visit involves a detailed medical history, one or more diagnostic tests, and a conversation about next steps. Most initial appointments take one to two hours, and you’ll often leave the same day knowing at least some of your results.
Your First Appointment: Medical History
Before any testing begins, the allergist will spend time asking questions. Expect to cover when your symptoms started, how often they happen, whether they’re seasonal or year-round, and what seems to make them better or worse. You’ll also discuss your family history of allergies and asthma, your home and work environments, and any medications you currently take. This interview matters because it helps the allergist narrow down which allergens to test for and whether your symptoms point toward allergies, asthma, or something else entirely.
Bring a list of your current medications. Certain drugs, especially antihistamines, need to be stopped about seven days before skin testing to avoid interfering with results. Your allergist’s office will typically tell you this when you schedule, but if they don’t, ask ahead of time.
Skin Prick Testing
The skin prick test is the most common diagnostic tool allergists use, and it’s faster than most people expect. A nurse or technician cleans a section of your forearm or back with alcohol, draws small marks on the skin, and places a drop of allergen extract next to each mark. A small lancet pricks each drop into the surface of the skin, using a fresh lancet for every allergen. This isn’t a deep needle stick; most people describe it as a light scratch.
The test typically screens for pollen, mold, pet dander, dust mites, and foods. Two control substances are also applied: histamine (which should cause a small bump in nearly everyone) and a neutral solution (which shouldn’t cause any reaction). These controls confirm the test is reading accurately.
After about 15 minutes, the allergist checks your skin for raised, reddish bumps at each test site. A visible reaction at a specific spot means you’re likely allergic to that substance. You’ll know your results before you leave the office.
When Blood Tests Are Used Instead
Some people can’t get reliable results from skin testing. If you have certain skin conditions like severe eczema, take medications that can’t be paused, or have very dark skin that makes reactions harder to read visually, your allergist may order a blood test instead. This test measures levels of an antibody called IgE in your blood. Everyone has some IgE, but elevated levels tied to a specific allergen signal an allergy.
Blood test results take longer since the sample goes to a lab. Different labs use different scoring systems, so your allergist will interpret the numbers for you rather than giving you a raw score to decode on your own. Skin tests tend to be more accurate overall, which is why they’re the first choice when possible.
Intradermal and Patch Testing
If your skin prick test comes back negative but the allergist still suspects a particular trigger, an intradermal test may follow. This involves injecting a tiny amount of allergen extract just below the skin’s surface on your arm with a fine needle. It’s more sensitive than a prick test and is commonly used to check for allergies to insect venom or penicillin. Results come in about 15 minutes.
Patch testing works differently and takes much longer. It’s designed for contact allergies, the kind that cause skin rashes from things like metals, fragrances, latex, hair dyes, or preservatives. Small patches loaded with potential allergens are applied to your back or arm, and you wear them for 48 hours without getting them wet. You then return to the office to have them removed and read. A final reading may happen at 96 hours, so this process can require two or three office visits spread over several days.
Breathing Tests for Asthma
Allergies and asthma overlap frequently, so many allergists check your lung function during the evaluation. The standard test is spirometry. You sit upright, clip your nose shut, take a deep breath, and blow as hard and fast as you can into a mouthpiece connected to a machine called a spirometer. You’ll repeat this at least three times to make sure the readings are consistent.
The machine measures how much air your lungs can hold and how quickly you can push it out. If the numbers suggest your airways are narrowed, the allergist may give you an inhaled medication to open them up and then repeat the test. If your breathing improves significantly after the medication, that pattern strongly suggests asthma. The allergist can also use spirometry over time to track whether your treatment is working.
Oral Food Challenges
When skin or blood tests suggest a food allergy but the picture isn’t clear, the allergist may recommend an oral food challenge. This is considered the gold standard for diagnosing food allergies, and it happens under close medical supervision.
You’ll eat gradually increasing amounts of the suspected food, typically in seven to nine small doses spaced 20 to 30 minutes apart. Staff monitor you for skin reactions, breathing changes, stomach symptoms, and any other signs of a reaction after each dose. If you develop clear symptoms like hives or vomiting, the challenge stops immediately and the team treats the reaction. If you reach the final dose without any problems, you stay under observation for at least two hours afterward. Delayed reactions can occasionally appear up to 24 hours later, so you’ll be asked to report any symptoms that develop at home.
Building a Treatment Plan
Once your triggers are identified, the allergist puts together a plan tailored to your specific results. This usually combines three approaches: avoidance strategies, medications, and in some cases, immunotherapy.
Avoidance strategies are practical recommendations for reducing your exposure. If you’re allergic to dust mites, for example, that might mean encasing your pillows and mattress, using a HEPA filter, or adjusting humidity levels in your home. For food allergies, the plan includes identifying hidden sources of the allergen in packaged foods and restaurants.
Medications are chosen based on which symptoms bother you most. The allergist will explain what each one targets and how to use it, whether it’s a daily nasal spray for congestion, eye drops for itching, or an epinephrine auto-injector for severe reactions.
For people with significant food allergies or a history of severe reactions, the allergist will create an emergency action plan. This document lists your specific allergens, describes the signs of a serious reaction, spells out when and how to use epinephrine, and includes emergency contact information. It’s designed to be shared with schools, workplaces, or anyone who might need to help during a reaction.
Allergy Shots and Long-Term Immunotherapy
If avoidance and medications aren’t enough, or if you want a more lasting solution, the allergist may recommend immunotherapy. Allergy shots work by gradually exposing your immune system to increasing amounts of your trigger, training it to stop overreacting.
The process has two phases. During the buildup phase, which lasts three to six months, you’ll receive shots one to three times per week, each containing a slightly higher dose of the allergen. Once you reach an effective dose, you enter the maintenance phase: one shot per month, continuing for three to five years or longer. Many people see significant, lasting improvement after completing the full course. Sublingual immunotherapy (tablets or drops placed under the tongue) is an alternative for certain allergens, and the allergist will discuss which option fits your situation.
What Makes an Allergist Different
Allergists complete medical school, a residency in either internal medicine or pediatrics, and then a separate two- to three-year fellowship focused specifically on allergy and immunology. That specialized training means they can distinguish between a true allergy and conditions that mimic one, interpret test results in context rather than at face value, and manage complex cases involving multiple triggers or overlapping conditions like asthma and eczema. A positive test result doesn’t always mean a clinically meaningful allergy, and a negative result doesn’t always rule one out. The allergist’s job is to connect the test data to your actual symptoms and build a plan that makes a real difference in your daily life.