What Is Allergic Rhinitis?

Allergic rhinitis (AR) is a common allergic disorder involving inflammation of the nasal passages after exposure to allergens. Across the world, about 3 in 10 adults and 4 in 10 children experience allergic rhinitis.

What Are Allergens?

Allergens are the things that cause an allergic reaction. Common allergens are pollen, dust, and animal fur. Some allergens are “in the air” all year round, or only present in certain locations (e.g., straw on a farm, or a dusty house), others have seasonal peaks (e.g., pollens).

What Are the Symptoms of Allergic Rhinitis?

The main symptoms are nasal itching, sneezing, rhinorrhea (snotty nose), and nasal congestion (blocked nose). However, these symptoms also lead to symptoms such as sleep problems, headaches, eye problems, sinus pressure, and pain. Research has shown that allergic rhinitis affects a person’s mental wellbeing and social functioning, as well as generally reducing their quality of life (when compared to those without allergic rhinitis).

What Happens During an Allergic Reaction?

When a person is first exposed to a particular allergen, there is an initial period of sensitization. Exposures after that result in an allergic response. An allergic response has two phases:

1. An initial phase: The release of inflammatory substances from cells known as mast cells. These lead to the stimulation of nearby nerve endings causing itching, blood vessel changes (angiogenesis and vasodilation) causing rhinorrhea and congestion, and the sneezing reflex.
2. A late phase: The arrival of inflammatory cells (e.g., eosinophils) and inflammatory substances (e.g., IL-4 cytokines). This inflammation results in the recurring symptoms.

How Is Allergic Rhinitis Typically Treated?

The Allergic Rhinitis and its Impact on Asthma (ARIA) guideline suggests anti-allergy pills (antihistamines) and nose sprays (corticosteroids) for the treatment of allergic rhinitis. However, in real-life, it is difficult for people to use these in the proper way, and, even if used the correct way, they do not always work.

What Non-Drug Options Are There?

Other methods for treating allergic rhinitis include immunotherapy, acupuncture, and low-level laser therapy (LLLT).

What Is Low-Level Laser Therapy?

LLLT is a novel, painless treatment method that uses low intensity light (laser) to reduce inflammation. The laser is focused on the affected area inside the nose. Without causing heat or damage, it can still improve cell processes and thus reduce the allergy responses described above. The laser is very low in power (less than 500 mW) and is thus sometimes known as “cool” laser or “soft” laser.

How Does LLLT Work?

The exact way that LLLT has an anti-inflammatory effect is not fully understood. But scientists know that it can decrease cell substances involved in the inflammation process such as TNF-α, cyclooxygenase-2, prostaglandin E2, and IL-1β.

What Did the Authors Do?

To find out about the effectiveness and safety of LLLT, the authors carried out what is called a systematic review and meta-analysis. They searched research databases for all research on “allergic rhinitis” and “low-level laser” therapy. There are international guidelines for how to do this in the best way: such as using special databases, using particular search words, and following logical processes to carefully review and categorize what is found. The authors ended up with 16 suitable studies. Half of these studies were published very recently (i.e., in the last 5 years), indicating great research interest in the topic.

What Did the Authors Assess?

They used the research and statistical methods to:

1. Make comparisons of people’s allergic rhinitis symptoms before and after LLLT.
2. Assess the safety of LLLT.
3. Make comparisons of LLLT effectiveness compared to no/dummy treatment (placebo), other laser types, and acupuncture treatment.

What Where the Results?

The analysis revealed that, after LLLT, people had less rhinitis nasal symptoms and improved quality of life. However, this “before and after” effect was very similar to the results of comparisons between placebo and LLLT treatment. Therefore, although it is probable that LLLT is helpful, further research needs to be done with larger groups of people, and with comparison between medicines and LLLT. It is hoped that this further research can confirm that LLLT is better than placebo and better than anti-allergy medication.