What are Allergies?

Allergies occur when the immune system overreacts to otherwise harmless foreign substances, called allergens. When an allergen enters the body, the immune system signals special cells - "mast cells" to release a substance called histamine.

Histamine release causes tissue swelling, increased secretions, itching, and tightening of the muscles that surround the airways - the characteristic allergy symptoms. Respiratory allergens such as pollen, mold, dust mites and animal dander cause relatively mild symptoms, such as runny nose, sneezing, congestion, rashes and itching, watery eyes.

Allergens can also trigger wheezing, breathing problems and asthma in some people. In the most severe case, allergens such as bee stings, penicillin and certain foods can induce a life-threatening collapse known as anaphylactic shock.

What is Hayfever?

Hayfever or allergic rhinitis is the allergic response to pollen from trees, grasses or weeds, and the severity usually depends on the season. Because the pollen allergens are airborne, the nose and eyes are affected most, giving hayfever sufferers the classic symptoms of runny nose, congestion, sneezing and itchy, watery eyes.

What is the best treatment for Allergies?

Ideally, preventing exposure to allergens is the best treatment. In the case of hayfever, this may involve staying inside in the early morning and late afternoon, and keeping windows closed while at home or in the car. Unfortunately, prevention is not always possible, so another option is to consider the effective drug treatments available.

Which Drugs are available to treat Allergies?

Antihistamines are probably the most common allergy medicines. Antihistamines work by blocking the effects of histamine, which causes the swelling and itching response to an allergen. Blocking histamine’s effects reduces allergy symptoms. Many over-the-counter antihistamines cause drowsiness and carry warnings against driving or operating machinery while taking them.

For further information see Antihistamines

There are newer non-sedating antihistamines available to help manage allergy symptoms without drowsiness.

Examples: Allegra (fexofenadine), Claritin (loratadine) and Zyrtec (cetirizine).

Antihistamine Nasal Sprays are used to treat the nasal symptoms of allergies.

Examples: Astelin Nasal Spray (azelastine) Livostin Nasal Spray (levocabastine)

Antihistamine Eye Drops ease the eye symptoms of allergic conditions, such as itching and watering.

Examples: Patanol Eye Drops (olopatadine), Emadine Eye Drops (emedastine), Livostin Eye Drops (levocabastine)

Decongestants work to clear the nasal passages by reducing the swelling caused by the histamine. They are intended for short term use and should not be used for more than a few days to prevent worsening of symptoms (called "rebound effect").

Example: Sudafed (pseudoephedrine)

Decongestants are available as nasal sprays and nasal drops.

Example: Otrivin Nasal Spray/Drops (xylometazoline)

Decongestants are also available as eye drops.

Example: Vasocon Eye Drops (naphazoline)

Antihistamine/Decongestant combinations are used to treat nasal congestion and other nasal allergy symptoms.

Examples: Claritin-D (loratadine/pseudoephedrine) and Allegra-D (fexofenadine/pseudoephedrine)

Antihistamine/Decongestant Eye Drops are available to treat redness, itching and watering of the eyes associated with allergic conditions.

Example: Naphcon-A Eye Drops (naphazoline/pheniramine)

Corticosteroid Nasal Sprays act by reducing inflammation and therefore preventing the symptoms of allergies. They are generally used long-term for the duration of the allergy season and may not take full effect until one or two weeks after initiating therapy.

Examples: Beconase (beclomethasone), Flonase (fluticasone), Nasacort (triamcinolone), Nasalide (flunisolide), Nasonex (mometasone), Rhinocort (budesonide)

Mast-Cell Stabilizing Drugs act by stabilizing the mast cells which release histamine, thereby preventing allergy symptoms. In the form of nasal sprays, mast-cell stabilizing drugs are intended for long-term preventative use and may require several weeks to be effective.

Example: Nasalcrom (cromolyn sodium)

Mast-cell destabilizing drugs are also available as eye drops.

Example: Alomide (lodoxamide), Crolom (cromolyn sodium), Alamast (pemirolast)

Nonsteroidal anti-inflammatory drugs (ophthalmic) reduce pain, itching and inflammation of the eyes associated with allergic reactions

Example: Acular (ketorolac)

Some over-the-counter products should not be used by people with certain medical conditions. Always check with your pharmacist before taking any medications.