💉 Allergy Immunotherapy: What’s the difference between SCIT & SLIT?

Allergy Immunotherapy (AIT) is a long-term treatment designed to retrain the immune system to tolerate allergens. The two primary delivery methods are Subcutaneous Immunotherapy (SCIT) and Sublingual Immunotherapy (SLIT), differing mainly in administration and safety profile.  SCIT, or "allergy shots," involves regular injections under the skin, initially frequent, then reducing to monthly doses for several years. SCIT is generally considered the most effective form, can treat a wide range of multiple allergens simultaneously, and is well-established. However, it requires all doses to be administered in a doctor's office due to a higher, though rare, risk of a severe systemic reaction. 
SLIT, or "allergy drops/tablets," involves placing the allergen under the tongue daily, which is then absorbed. Its key advantage is convenience, as the daily dose is taken at home (after the first dose in-office). SLIT has a significantly lower risk of systemic reactions. Currently, SLIT tablets are FDA-approved for a limited number of specific allergens (like grass and dust mites), making SCIT the preferred choice for patients with complex or multiple allergies.  Both methods aim to induce long-lasting immune tolerance by producing blocking antibodies and regulatory cells.

SLIT is both FDA & DCGI approved and SCIT is only FDA approved.

Dr. Aditi Shah
Dr. Pravin Taware