Allergist Day is observed in Russia and some other former Soviet republics every October 16. Although it is not officially recognized, it is sometimes referred to as World Allergist Day. This day celebrates allergists and immunologists, who specialize in diagnosing and treating allergies. The term "allergy" was coined in 1906 by Austrian pediatrician Clemens von Pirquet, who observed severe reactions in patients after smallpox vaccinations. Allergic reactions can be triggered by a wide range of allergens, including pollen, dust mites, food, and insect bites, with symptoms varying from sneezing and runny nose to severe anaphylaxis. Events such as conferences, seminars, and lectures are held to mark the occasion, highlighting the importance of the profession.