Nasal allergy is most often due to –
**Core Concept**
Nasal allergy, also known as allergic rhinitis, is an inflammatory condition of the nasal passages triggered by an immune response to inhaled allergens. This condition is mediated by IgE antibodies and involves the release of histamine and other chemical mediators from mast cells.
**Why the Correct Answer is Right**
Allergic rhinitis is most often caused by allergens such as pollen from trees, grasses, and weeds, as well as dust mites, mold, and pet dander. When these allergens enter the nasal passages, they bind to IgE antibodies on the surface of mast cells, leading to the release of histamine and other chemical mediators. This results in symptoms such as sneezing, runny nose, and nasal congestion.
**Why Each Wrong Option is Incorrect**
**Option A:** Other options, such as viral infections, anatomical abnormalities, or environmental irritants, may also cause nasal symptoms, but they are not the primary cause of allergic rhinitis.
**Option B:** While non-allergic rhinitis can be caused by irritants such as tobacco smoke or strong odors, it is not the most common cause of nasal allergy.
**Option C:** Invasive fungal sinusitis is a rare condition that can cause nasal symptoms, but it is not related to allergic responses.
**Clinical Pearl / High-Yield Fact**
The most common allergens responsible for allergic rhinitis can vary depending on the geographic location and time of year. In the spring, tree pollen is a common culprit, while grass pollen is more prevalent in the summer.
**Correct Answer:** D.