What type of allergy does the patient's sister have?

The patient's sister has hay fever, which is also known as allergic rhinitis. This condition is characterized by an allergic reaction to airborne allergens, particularly pollen from trees, grasses, and weeds, that can trigger symptoms such as sneezing, runny or congested nose, and itchy eyes. It is common for individuals with hay fever to experience these symptoms during certain seasons when pollen levels are high, making it a prominent issue especially in spring and summer.

While dust allergies and pollen allergies could be factors in allergic reactions, they are more specific subsets of potential allergens. Dust allergies generally refer to reactions to dust mites, and pollen allergies are broader but do not convey the same seasonality and broader context that hay fever encompasses. Food allergies involve a different mechanism altogether, where the immune system reacts against specific proteins in food items, and they trigger different symptoms. Understanding these distinctions is vital in the context of allergy diagnosis and management.