Indoor allergy (perennial allergic rhinitis)

An indoor allergy is when something in your home or work environment triggers an allergic reaction that causes the lining of your nose to become inflamed and swollen. This can cause cold-like symptoms such as:

• sneezing,
• a runny nose, and
• nasal congestion.

The symptoms of an indoor allergy can range from mild to severe. While an indoor allergy is not a life-threatening condition, it can have a considerable impact on quality of life. It can also affect sleep, daily activities and performance at work or school.

An indoor allergy is also known as perennial allergic rhinitis. The word perennial is used because the symptoms can occur all year round, unlike the seasonal types of allergic rhinitis, such as hay fever, which is caused by an allergic reaction to certain types of pollen.

Allergens

Anything that can cause an allergic reaction is known as an allergen. The most common triggers of an indoor allergy are:

• dust mites,
• fungus spores,
• pets, in particular the dead skin that is shed by pets, known as animal dander, and
• substances related to particular occupations or workplaces, such as wood dust and chemicals.

How common are indoor allergies?

Indoor allergies are very common. It is estimated that 10-20% of the population has an indoor allergy. Most indoor allergies first develop during childhood or early adulthood, with 80% of cases developing before a person is 20 years old. Men and women are equally affected by indoor allergies.

Outlook

In some cases, the symptoms of an indoor allergy can be reduced by using a treatment called immunotherapy. This involves an affected person being exposed to small amounts of allergen over time so that their body builds up a tolerance to the allergen.

The main disadvantage of immunotherapy is that it is time consuming, taking three to five years to complete. It is also not suitable for everyone.

Because immunotherapy takes a long time, it is recommended that most people with a mild to moderate indoor allergy use medication to control their symptoms and, when possible, limit their exposure to the offending allergen.