Hay fever, also known as allergic rhinitis, is an allergic reaction that occurs when the immune system overreacts to airborne substances such as pollen, dust mites, mould spores, or animal dander. It is a common seasonal condition, though some people experience symptoms all year round. When these allergens are inhaled, the body releases histamine and other chemicals, leading to inflammation of the nasal passages and surrounding tissues.
Typical symptoms include sneezing, a runny or blocked nose, itchy eyes, and throat irritation. Many people also experience fatigue, headaches, and difficulty concentrating, especially during high pollen seasons. Symptoms often worsen outdoors on dry, windy days when pollen levels are high or indoors where dust or pet allergens are present.
Hay fever can be triggered by different types of pollen, depending on the season. Tree pollen is most common in spring, grass pollen in summer, and weed pollen in late summer and autumn. Indoor triggers such as dust mites and pet hair can cause year-round symptoms known as perennial allergic rhinitis.
