Do Allergy Shots Have Steroids in Them? What Is Actually in the Vial

The confusion arises because corticosteroid injections — specifically Kenalog (triamcinolone acetonide) and Depo-Medrol (methylprednisolone) — are sometimes given for acute allergy flares or seasonal allergy management, and are colloquially called 'allergy shots' in everyday conversation and even in some primary care settings. Seidman et al. (Otolaryngol Head Neck Surg 2015) documented this terminology overlap as a significant source of patient confusion. Adding to the confusion, both SCIT and Kenalog are administered by injection, often by the same type of clinician. But they are fundamentally different: one contains allergen proteins to retrain immunity, the other contains corticosteroids to suppress inflammation temporarily.

A standard SCIT vial contains purified allergen extracts — proteins derived from the specific allergens causing your symptoms. For grass pollen allergy, this means Phl p 5 and related grass proteins. For dust mite allergy, it means Der p 1 and Der f 1 mite proteins. For cat allergy, it is Fel d 1. For stinging insect allergy, it is venom proteins at 100 micrograms maintenance. These proteins are suspended in preservative solution: typically 50% glycerin, or human serum albumin (0.03%) plus phenol (0.4%). Some European depot formulations use aluminum hydroxide as an adjuvant. No corticosteroids, antihistamines, or biologics are present in any FDA-cleared SCIT formulation.

Kenalog (triamcinolone acetonide) is an intramuscular corticosteroid injection — a potent synthetic glucocorticoid that broadly suppresses immune and inflammatory activity for 2 to 6 weeks. It is sometimes given by primary care physicians or ear-nose-throat specialists for acute allergy flares, seasonal rhinitis management, or other inflammatory conditions. It is not immunotherapy and it is not the same as an allergy shot. Repeated Kenalog use carries cumulative risks including adrenal suppression (the adrenal glands stop producing cortisol normally), bone density reduction, blood sugar elevation, and increased infection susceptibility. SCIT carries none of these risks because it contains no corticosteroids.

While occasional short courses of corticosteroids (like a prednisone taper for a severe allergy flare) are generally acceptable alongside ongoing SCIT, regular or repeated corticosteroid injections during SCIT treatment are not recommended. The reasons are both practical and immunological: systemic corticosteroids may theoretically blunt the Treg-induction response that SCIT depends on, and frequent steroid shots (like quarterly Kenalog) are associated with cumulative side effects regardless of SCIT status. Most allergists recommend optimizing SCIT and environmental controls first, rather than supplementing with repeated steroid injections. Your allergist can advise on managing acute flares while maintaining the integrity of your SCIT program.

No — allergy shots (SCIT) do not cause steroid side effects. Because SCIT contains no corticosteroids, patients do not experience adrenal suppression, bone density loss, weight gain, fluid retention, glucose elevation, or broad immunosuppression associated with repeated steroid injections. SCIT does carry its own specific side effects: local injection site reactions (redness, swelling, itching in 26 to 86% of patients) and a small systemic reaction risk (approximately 0.1% per injection). These are fundamentally different in nature and mechanism from steroid side effects. A 30-minute post-injection observation traditionally managed them in the allergist's office; with Curex, eligible at-home patients keep a prescribed epinephrine auto-injector confirmed on hand, have their first injection and every dose change supervised live over Zoom, and escalate the dose gradually week by week under board-certified allergist oversight.

No — sublingual allergy drops (SLIT) are allergen extracts administered under the tongue for immune retraining, not corticosteroids. Steroid nasal sprays (fluticasone, mometasone, budesonide) contain corticosteroids that reduce nasal inflammation locally, providing symptom control without any disease modification. SLIT drops contain the same types of allergen proteins as allergy shots — pollens, dust mite proteins, animal dander — and work through the same immune-retraining mechanism as SCIT, inducing Tregs and IgG4 blocking antibodies. SLIT drops produce no steroid side effects and do not interact with the hypothalamic-pituitary-adrenal axis.