What Are Allergy Injections? Types, Differences and Uses

Allergy shots (SCIT) and Kenalog (triamcinolone acetonide) injections are fundamentally different treatments. Allergy shots contain allergen extract proteins that gradually retrain your immune system over 3–5 years — they are disease-modifying and their benefits can outlast treatment. Kenalog is a synthetic corticosteroid that suppresses the immune response broadly and provides 2–6 weeks of symptom relief. Kenalog is not disease-modifying — when the steroid effect wears off, allergy symptoms return unchanged. AAAAI and ACAAI recommend against routine corticosteroid injections for allergic rhinitis due to risks of adrenal suppression, bone density loss with repeated use, and hyperglycemia. If you are unsure which injection your provider gave you, ask: allergy shots require allergy testing first and a series of many injections, while Kenalog is a single injection available without prior testing.

Xolair (omalizumab) is a biologic injection — a monoclonal antibody that targets IgE, the antibody responsible for triggering allergic reactions. It binds to free IgE in the bloodstream, preventing IgE from attaching to mast cells and basophils, thereby reducing allergic reactivity. Unlike allergy shots, Xolair does not target specific allergens — it broadly reduces IgE-mediated reactions. It is FDA-approved for moderate-to-severe allergic asthma (in patients over 6 years with year-round sensitization), chronic idiopathic urticaria, and nasal polyps. Xolair costs approximately $1,000–3,000 per month. Allergy shots target the specific allergens driving your symptoms and provide disease modification; Xolair requires ongoing treatment to maintain benefits. Some allergists use Xolair before starting SCIT in highly sensitized patients to reduce the risk of reactions during build-up.

Biologic injections and allergy shots treat different aspects of allergic disease and are not directly interchangeable. Allergy shots work best for IgE-mediated environmental allergies (rhinitis, asthma, venom) in patients who can commit to 3–5 years of treatment — they address the root cause by retraining antigen-specific immunity. Biologic injections like Dupixent (dupilumab) are preferred for patients with severe type 2 inflammatory conditions (atopic dermatitis, severe asthma with eosinophilia, nasal polyps) that have not responded adequately to other treatments. Biologics work faster than immunotherapy but require indefinite ongoing treatment, and their costs are significantly higher. In practice, a board-certified allergist will evaluate your specific diagnosis, disease severity, and treatment history to determine whether immunotherapy, a biologic, or combination therapy is most appropriate.

Corticosteroid injections (Kenalog) and some biologic injections can be administered by GPs, urgent care physicians, and pulmonologists. However, allergen immunotherapy injections (SCIT) should only be administered by or under the direct supervision of a board-certified allergist. This is because SCIT requires allergy skin testing to identify your specific IgE sensitization profile, a custom allergen extract formulated for your individual triggers, and the capacity to manage anaphylaxis — which requires trained staff, epinephrine, and resuscitation equipment on-site. AAAAI and ACAAI practice parameters state that immunotherapy must be performed in a setting with appropriate emergency equipment and personnel. Receiving SCIT injections without these safety measures significantly increases risk.

Epinephrine (adrenaline) auto-injectors like EpiPen are emergency rescue injections for anaphylaxis — not a treatment for chronic allergies. They contain 0.3 mg (adult) or 0.15 mg (pediatric) epinephrine and are administered intramuscularly into the outer thigh during a severe allergic reaction. Their effect lasts only 10–20 minutes, which is why 911 should always be called even after using an auto-injector. Epinephrine injections do not modify the immune system and do not reduce future allergy risk. They are distinct from both allergen immunotherapy shots and corticosteroid injections. Patients at risk for anaphylaxis — including those undergoing allergy shots — are typically prescribed epinephrine auto-injectors to carry at all times.

Outside North America, the terminology differs — 'allergy injections' or 'desensitisation injections' is more common than 'allergy shots.' The same three categories apply: allergen immunotherapy (subcutaneous or sublingual), corticosteroid injections, and biologics. A key difference internationally is that depot allergen preparations — formulations using aluminum hydroxide or tyrosine adjuvants to slow allergen release — are approved in Europe and some other countries but are not FDA-approved in the United States, where only aqueous extracts are used. European practice guidelines (from EAACI) and US practice parameters share similar fundamental protocols for immunotherapy, though specific allergen extracts, dosing schedules, and regulatory requirements differ. If you have received allergy injections abroad, share your treatment records with your US allergist to determine the equivalent US approach.