Allergy and Anaphylaxis

Allergy can present in different ways. Red, itchy lumps can occur anywhere on the body. Inhaled allergens eg pollens can cause an itchy runny nose and sneezing. An allergen can precipitate asthma. There are many different medications that can be used for an allergic reaction. First generation antihistamines such as promethazine (Phenergan) are very effective but can cause drowsiness and sedation. Newer antihistamines work more slowly, last longer and do not cause sedation e.g. Telfast, Zyrtec, Claratyne. Sprays are available for acute nasal allergy.

Promethazine HCL 25mg = Phenergan. Dexchlopheniramine maleate 2mg = Polaramine.

Useful to stop itching due to skin allergy from contact dermatitis, or after insect bites. It is useful for hayfever; it will help dry the nose and clear the eyes. Adult dosage: Take 1 tablet every 6-8 hours. It may also assist motion sickness. Adult dosage: Take 1 tablet the night before travel and another the morning of travel.

IMPORTANT: May cause drowsiness. Do not drink alcohol or operate machinery whilst taking this medication. Best taken before bed.

Non-sedating antihistamines can be used in the daytime to supplement promethazine at night.

These include:

Fexofenadine HCL = Telfast. Adult dosage: Take 120mg to 180 mg once daily.

Loratadine = Claratyne. Adult dosage: Take 1 tablet (10mg) daily. Cetirizine = Zyrtec: Adult dosage: Take 1 tablet (10mg) daily. Paediatric formulations are available.

• Swelling or itching of the lips
• Facial swelling or redness
• Unexplained coughing or wheezing
• Breathing difficulties or rapidly developing rash

Urgent medical attention may be required. Treatment with adrenaline and steroids can be lifesaving.
Travellers at risk of anaphylaxis through bites, stings, food or medications should always carry an Epipen and a fast-acting antihistamine.

Anaphylaxis plans can be viewed at allergy.org.au