Hay fever- Part 2
Hay fever is a type of allergic rhinitis caused by pollen or spores.
The doctor will ask questions to determine cause and type of allergy. The doctor will examine the inside of the nose with an instrument called a speculum. The eyes, ears, and chest may be examined.
Skin tests may be performed. Patients are usually tested for a panel of common allergens. Skin tests are rarely needed to diagnose mild seasonal allergic rhinitis, since the cause is usually obvious. Patients should not take antihistamines for 12 to 72 hours prior to the skin test otherwise the allergy will not show up. Tiny amounts of suspected allergens are applied to the skin with a needle prick or scratch. Skin allergy tests are not 100% accurate.
The doctor may take a nasal smear. The nasal secretion is examined microscopically for factors that might indicate a cause, such as increased numbers of white blood cells, indicating infection, or high eosinophil count indicating an allergic condition. Blood tests for IgE immunoglobulin production may also be performed.
As total avoidance of triggers like pollen is impossible, medication is often needed to control symptoms.
Oral antihistamines are effective in relieving eye symptoms, running nose, sneezing and nasal irritation but have negligible effect on nasal congestion. Antihistamines are useful in patients with troublesome symptoms at multiple sites e.g. itching of roof of the mouth, throat or eyes.
First Generation Antihistamines. ("Sedative")
Sedation is the most common side effect of these drugs and may affect the patient’s ability to drive and operate machinery and concentrate. They should not be used in patients with prostatic hypertrophy or narrow angle glaucoma. Tolerance to their side effects may develop. Chlorpheniramine (Piriton®) is available over the counter in pharmacies.
Second Generation Antihistamines. ("Non- Sedative")
Examples include desloratadine (Neoclarityn®), fexofenadine (Telfast®), levocetirizine (Xyzal®), loratadine (Clarityn®) and cetirizine (Zirtek®, Cetrine®). They only require once daily dosage and are non-drowsy. Loratadine and cetirizine are available over the counter without prescription. The non-sedating antihistamines are fast acting, have no reported cardiac side effects, and are not affected by the presence of food in the stomach. However, loratidine is best avoided in elderly patients and patients with liver problems. Whelehans now provide Cetrine Allergy® (a non-drowsy antihistamine) in a cost-effective pack of 30 for €4.
To be continued… next week