How to Get an Allergy Shot: One-Time Relief vs Starting Immunotherapy

It depends on which type of allergy shot you want. A corticosteroid injection for acute allergy symptom relief is available at urgent care clinics, emergency rooms, and most primary care offices without an allergist referral — any licensed physician or advanced practice provider can administer it. Allergen immunotherapy, however, requires a prescription from a physician qualified in allergy — typically a board-certified allergist or an ENT with allergy training. The immunotherapy prescription determines your specific allergen extract formulation based on confirmed allergy testing results. You cannot get the immunotherapy version of an allergy shot at urgent care or without the specialist evaluation, allergy testing, and custom extract preparation that allergen immunotherapy requires.

A single corticosteroid injection such as triamcinolone acetonide (Kenalog) at 40-80 mg typically provides symptom relief lasting 2-6 weeks, depending on the dose, the individual's metabolism, and the allergen burden in their environment. Symptom control usually begins within 24-48 hours of the injection as the steroid takes effect. As the steroid gradually metabolizes, symptoms may return toward the end of the effective window — often gradually rather than all at once. Some patients notice relief lasting closer to 2-3 weeks; others report 4-6 weeks of meaningful symptom suppression. The relief is not allergen-specific — it broadly reduces allergic inflammation regardless of which allergens you are sensitive to, which is why it works quickly but doesn't address the underlying cause.

Starting allergen immunotherapy (allergy shots for long-term desensitization) involves several steps over 6-10 weeks. First, ask your primary care physician for a referral to a board-certified allergist — or find one directly using the AAAAI allergist finder at allergist.aaaai.org. At the allergist consultation, you will complete allergy testing (skin prick testing or a blood-based specific IgE panel) to identify your allergen sensitivities. Based on results, the allergist creates a personalized extract formulation and treatment plan. Your allergist's office then submits insurance pre-authorization (1-3 weeks) and prepares your custom extract (2-4 weeks). Once both steps are complete, you attend your first injection visit to begin the build-up phase — weekly injections for approximately 6 months, then monthly maintenance for 3-5 years.

One corticosteroid injection provides temporary symptom relief for 2-6 weeks but does not address the underlying allergy mechanism. Once the steroid effect wears off, your allergy symptoms return with the next allergen exposure. It is not a cure or a treatment — it is symptom suppression. Allergen immunotherapy, in contrast, requires a full course of injections over 3-5 years to achieve lasting tolerance. A 2007 Cochrane review of 51 randomized trials found that SCIT significantly reduced rhinitis symptom scores and medication use, with benefits that can persist for several years after stopping treatment per Durham et al. (NEJM, 1999). So one shot of the immunotherapy variety is just the first of many — the benefit builds cumulatively over the treatment course.

Getting a Kenalog (triamcinolone acetonide) corticosteroid injection for allergy symptoms is straightforward: call your primary care physician's office or an urgent care clinic near you and describe your symptoms. Most practices can provide this injection during a same-day or next-day appointment. You do not need allergy testing, a specialist referral, or prior authorization. At the appointment, a physician, PA, or NP will briefly evaluate your symptoms and, if appropriate, administer the intramuscular injection (usually into the deltoid or buttock). The total visit takes 20-30 minutes. The cost is typically $150-$350 for the urgent care visit plus $30-$80 for the injection itself. Note that Kenalog injections are a short-term management tool — if you need more than 2-3 per year, discuss long-term allergy treatment options with your doctor.

Allergen immunotherapy requires a confirmed allergy diagnosis before treatment can begin. The standard tests are skin prick testing and specific IgE blood testing. Skin prick testing is performed in the allergist's office: small amounts of standardized allergen extracts are applied to the forearm or back skin via tiny punctures, and reactions (wheal and flare) are measured after 15-20 minutes. Specific IgE blood testing (also called RAST or ImmunoCAP testing) measures the level of IgE antibodies to specific allergens in a blood sample and can be ordered by any physician or through at-home testing services. Both tests identify which specific allergens your immune system is sensitized to, allowing the allergist to formulate a personalized allergen extract targeting your actual triggers. Testing is the clinical foundation — without it, immunotherapy cannot be safely prescribed.