What are some common symptoms of allergies?

The symptoms of many allergic conditions may be specific to them. For example, wheezing in asthma, or irritated eyes (allergic conjunctivitis) in hay fever Symptoms can vary depending on where they are in the body, which in turn depends on how you are exposed to the allergen.

Airborne allergens, such as pollen or dusts, mainly affect the eyes, nose, and airways. The nasal lining may become inflamed and may start making lots of mucus – this can be seen in hay fever Irritation of the nose can lead to sneezing. The eyes can become itchy, watery, and painful – this is known as allergic conjunctivitis, and is again seen in hay fever If allergens are inhaled, they can cause airways to tighten (bronchoconstriction) leading to shortness of breath and wheezing, and/or increased mucus production, which can also cause some difficulty in breathing. The sinuses in the head (known as the paranasal sinuses) can also become infected and inflamed – this is known as allergic sinusitis. Ears may also be affected, and can feel full. They may also be in pain, and hearing may be impaired.

Substances that come into contact with the skin, such as creams or latex, can cause localised reactions on the skin. Rashes and inflammation is extremely common in skin reactions. Common symptoms include eczema, hives (urticaria), or angioedema (swelling caused by leaky blood vessels). Angioedema and urticaria are extremely similar, but angioedema occurs deeper in the skin. Urticaria and angioedema can also occur as part of a systemic (whole-body) reaction, and are common in allergic reactions to food. Angioedema and urticaria can happen over a course of hours or minutes, and can remain for several days. Angioedema most commonly affects the face and hands, and can even cause airway obstruction. It must be noted that allergy is not the most common cause of hives (20 % of hives are caused by allergy).

Food allergies can often cause gastrointestinal symptoms, such as bloating, abdominal pain, vomiting, or diarrhoea, as well as reactions on the skin. However they rarely cause any respiratory symptoms. Allergic reactions to insect stings and certain medicines or foods can produce effects throughout the entire body in an extremely severe reaction known as anaphylaxis. This can lead to shock, coma, or even death if left unattended, but can easily be treated with an injection of adrenaline.

Allergies Guide Index:

• What are allergies?
• What's the difference between allergies, intolerance, and sensitivity?
• Overview of the immune system
• How do allergies happen?
• Who gets allergies?

• What are some common symptoms of allergies?
• What are some common allergies?
• How can I check to see what I'm allergic to?
• What treatment options are available?