Allergy Shots: What to Expect Before, During and After

From completed allergy testing to your first injection, expect approximately 2–4 weeks. Insurance pre-authorization for immunotherapy can take 1–2 weeks, and your custom allergen extract vial requires 1–2 weeks to prepare after your allergist receives your test results and formulates the prescription. Some insurance plans require prior authorization and may request additional documentation. Once the extract is ready and insurance is confirmed, your first appointment is scheduled. Some allergy practices can expedite the process in 1–2 weeks for patients without insurance hurdles. The timeline varies by practice, insurance carrier, and extract manufacturer availability. Ask your allergist's office coordinator for an estimated timeline specific to your situation.

After your first allergy shot, plan a full 30-minute observation window before resuming other activities. With Curex at-home SCIT, your first injection is supervised live over Zoom by the prescribing allergist, who monitors you in real time during this window — a prescribed epinephrine auto-injector is confirmed on hand before the session begins. Local redness, swelling, and mild itching at the injection site are normal within 15–30 minutes of the injection and may persist for several hours. Applying ice reduces swelling and discomfort. For the remainder of that day, avoid vigorous exercise for 2 hours and hot showers for 1 hour. You may experience mild fatigue in the hours following your first few injections as your immune system begins responding to the allergen exposure. Monitor for any delayed symptoms — generalized hives, nasal symptoms, or asthma flare — over the next 24 hours and contact your allergist if they occur.

Missing allergy shot appointments during the build-up phase requires dose adjustment when you return. If you miss one week, your allergist may continue at the same dose or slightly reduce it; if you miss two or more weeks, a more significant dose reduction is typically required to ensure safety. Frequent missed appointments slow your progress toward maintenance and may reduce long-term efficacy. During the maintenance phase, spacing injections further apart than recommended (beyond 6–8 weeks) similarly requires dose reduction. Life happens — communicate with your allergist's office when you need to miss or reschedule. Most practices have written protocols specifying exact dose adjustments based on the number of days since your last injection.

Allergy shot treatment requires several consistent lifestyle adjustments: avoid vigorous exercise for at least 2 hours before and after each injection (increased blood flow accelerates allergen absorption); avoid hot showers or baths for 1 hour post-injection; disclose all new medications at every appointment, particularly beta-blockers and ACE inhibitors (both can complicate anaphylaxis treatment); and carry an epinephrine auto-injector (EpiPen) if prescribed for high-risk patients. You should avoid receiving an injection when acutely ill with fever, during significant asthma flares, or when your peak flow is substantially below baseline. Seasonal considerations include informing your allergist during peak pollen seasons for allergens in your extract — dose adjustments may be made to reduce systemic reaction risk.

Most patients notice the first meaningful symptom improvement 3–6 months into treatment, typically corresponding to the late build-up or early maintenance phase. Some patients experience their first noticeable benefit during the first pollen season after starting shots — even if that occurs relatively early in the build-up phase. Full therapeutic benefit, including the greatest reduction in medication use and the most sustained disease modification, typically develops over 12–18 months of consistent treatment. The immunological changes — IgG4 blocking antibody production begins within 4–8 weeks, regulatory T-cell induction develops over years — explain why early partial improvement gives way to more complete benefit with continued treatment.

Some patients report increased allergy symptoms in the first weeks of treatment, particularly around injection days. This is not unusual — early injections introduce allergen proteins that produce a controlled low-level immune response, which can temporarily increase nasal or eye symptoms in the hours following an injection. This is distinct from a systemic allergic reaction (hives, wheezing, widespread symptoms) and typically resolves within hours. Fatigue and mild soreness at the injection site are also common initially. As treatment progresses and IgG4 blocking antibodies accumulate, the post-injection flares typically diminish. If you are consistently experiencing significant symptom worsening with each injection, discuss this with your allergist — dose adjustment may be appropriate.