Allergies

Allergic rhinitis, including Hay fever and its more persistent form, perennial allergic rhinitis, is a common condition affecting up to 25% of the population. While it is often considered a minor ailment, it can significantly impair quality of life due to symptoms such as a runny nose, sneezing, itchy eyes, and nasal congestion. Patients may also experience fatigue, sleep disturbances, cognitive difficulties, and mood changes. Allergic rhinitis is closely linked to other health problems such as chronic sinusitis, asthma exacerbations, nasal polyps, and sleep apnoea.

Allergic rhinitis can manifest in two primary forms: seasonal (Hay fever) and perennial.

• Seasonal allergic rhinitis is triggered by environmental allergens like tree and grass pollen and is prevalent during spring and summer (March to June). Typical symptoms include intense nasal and eye itching, sneezing, watery eyes and nose, itchy palate, and post-nasal drip. Seasonal allergy sufferers may experience puffiness around the eyes and swelling in the nasal membranes.
• Perennial allergic rhinitis, often described as a "permanent cold," occurs year-round due to allergens like house dust mites, pet dander, cockroach droppings, and mold. Symptoms are more subtle, including constant nasal blockage, snoring, loss of smell and taste, and occasional sneezing upon waking. This form of rhinitis can lead to chronic sinusitis, nasal polyps, and glue ear.

In chronic cases, patients may develop distinct facial features known as the "allergy face," which includes allergic shiners (bluish discoloration of the lower eyelids), Dennes lines (creases under the eyelids), and the "allergic salute," a habitual nose rub resulting in a nasal crease. Chronic nasal obstruction can also cause mouth breathing, a high-arched palate, and dental malocclusion, known as "long face syndrome."

Diagnosing allergic rhinitis typically involves a combination of patient history, symptom observation, and allergen identification. Skin prick tests or blood tests can be used to identify specific allergens triggering the allergic response.

In 1999, the World Health Organization introduced the ARIA (Allergic Rhinitis and its Impact on Asthma) Guidelines, which classify allergic rhinitis as Intermittent or Persistent rather than seasonal or perennial. This classification helps streamline treatment, which is adjusted based on whether symptoms are mild or moderate/severe.

The underlying cause of allergic rhinitis involves an immune reaction, often due to a genetic predisposition (atopy), where the body produces IgE antibodies against inhaled allergens such as pollen, dust mites, or pet dander. The release of histamine and other inflammatory chemicals causes symptoms like nasal congestion, sneezing, and itching.