A 26-year-old male presented with symptoms of rhinorrhea, sinusitis, epiphora (watering eyes), pharyngitis and fatigue.

He reported of having recently adopted a dog from the animal shelter. However, the patient was confused whether experiencing symptoms from animal dander because he did not experience these allergies until approximately a week after adopting the dog.

The patient’s vital signs were normal. Physical examination elicited dry skin, small, raised bumps on the chest, along with red-brown patches on the chest and legs behind the knees.

Once the results of the diagnostic tests are finalized, the physician determined that the patient’s diagnosis is allergic rhinitis, commonly known as “Hay fever.” The culmination of the diagnostic tests including the complete blood count and differential which showed leukocytosis and eosinophilia, the increased IgE antibody using RIST, and the positive percutaneous skin test to dog dander is what led to this diagnosis

Eosinophils play very important roles in the immune system including destroying foreign substances and inflammation regulation, along with other kinds of white blood cells. Eosinophils have brilliant and noticeable pink-orange granules that contain histamine. When histamine is released from eosinophils, this chemical stimulates allergic reactions such as what the patient with allergic rhinitis was exhibiting, noticeably so rhinorrhea and itchy eyes. Allergic rhinitis is classified as a type I hypersensitivity reaction which is defined as IgE mediated. In these types of reactions, a patient is exposed to an allergen (antigen), and when first exposed to the antigen, the patient may not experience symptoms because the cascade of biochemical events is not yet activated until a second exposure.

The most basic and self-evident method of prevention of allergic reactions is allergen avoidance.