Allergic rhinitis and asthma are common chronic conditions that affect a significant portion of the world’s population. Allergic rhinitis impacts approximately 18% of people worldwide and occurs in an estimated 24% of Singaporeans. This is due to the country’s tropical climate and high humidity levels. Meanwhile, asthma affects around 10.5% of Singaporeans throughout their lifetime, with a prevalence of 3.9% in adults aged 18–69, according to a study conducted by the National Health Survey.
They are both atopic diseases. Atopic means a person with a familial tendency to develop an allergic response, such as allergic rhinitis, asthma, or atopic dermatitis (eczema), in response to an allergen. Allergic rhinitis and asthma often co-exist within the same patient, both in children and adults. Asthma has been diagnosed in up to 38% of patients with allergic rhinitis. Allergies are also a common reason for asthma flares.
Despite that, allergic rhinitis and asthma are still two different conditions that affect different parts of your airway and may require different methods of treatment. We sit down with ENT specialist Dr. Liu Jiaying and respiratory specialist and interventionist Dr. Alvin Ng as they delve deeper into these two conditions, what they have in common, and how they can be managed.
Although your body’s immune system is there to help fend off germs and bacteria, allergic rhinitis happens when your immune system overreacts to harmless inhaled substances such as pollen, dust, or animal dander by releasing a chemical called histamine. It is the inflammation of the nasal lining or the nasal mucosa. Allergic rhinitis has a prevalence of 44–48% in school-aged children in Singapore.
Allergic rhinitis can be triggered by several indoor and outdoor allergens. Common ones include pollen from plants, mold spores, pet dander, dust mites, and droppings from pests.
According to Dr. Liu, some common symptoms of allergic rhinitis she sees in her patients include a blocked nose, runny nose, itchy nose, sneezing, and some people even get itchy eyes, watery eyes, or red eyes.
“If you have two or more of the following symptoms, then I think you need to consider that you might have allergic rhinitis,” she adds.
Asthma is caused by the chronic inflammation of your lung airway and results in the tightening of muscles in the airway, making it harder to breathe. Symptoms of coughing include coughing, wheezing, shortness of breath, and chest tightness. Although it may be a serious condition, asthma can be managed with the right treatment and medication.
Allergic rhinitis and asthma are both atopic diseases and are triggered when something in your environment mistakenly causes your immune system to be triggered, resulting in your airways becoming inflamed. They also share some common symptoms.
“One common presentation is a chronic cough,” says respiratory specialist Dr. Alvin Ng. “They keep coughing and coughing and coughing, and sometimes just treating the nose alone is not enough, you’ll need to treat the lungs. Sometimes, treating the lungs is not enough, and you’ll need to treat the nose.”
Although you can develop both conditions at any age, allergic rhinitis and asthma usually begin in childhood. A study has also shown that up to 75% of people with asthma also develop allergic rhinitis.
Dr. Liu adds that as the nose and lungs are part of a unified airway, “allergic rhinitis can cause problems such as excessive mucus production, which would then drip from the back of the nose all the way down. This irritates the larynx, which would then trigger irritation of the lungs.”
“That’s how allergic rhinitis can also exacerbate asthma,” says Dr. Liu
Despite their similarities, the conditions affect different parts of the respiratory system. With allergic rhinitis, you will experience nasal symptoms. Such as a congested nose, an itchy and runny nose, and also eye irritation and an itchy throat with post-nasal drip, which may result in coughing.
Asthma, on the other hand, affects your lungs, asthma symptoms are mostly in the chest. You will likely experience wheezing, shortness of breath, and tightness of the chest.
If you experience a persistent, lingering cough after recovering from COVID-19, you may be wondering if you are suffering from long COVID. A term used to describe symptoms that develop and linger even after recovering from COVID-19.
However, Dr. Ng states that there may be other reasons for your prolonged coughs.
“We know for a fact that viral infections trigger off asthma, and it is one of the factors that can trigger your asthma. So, my suggestion is that if you do have a lot of coughing that lasts longer than others after infection, then do see a doctor,” says Dr. Ng. “And if it doesn't get better, consider seeing a lung specialist, you can run a lung function test for you, and then try to tease out this diagnosis of chronic cough secondary to asthma.”
Dr. Ng also sees patients with chronic coughs who worry that it may be a sign of lung cancer. “They’ll ask me, ‘Doctor, is this cough cancer?’ So, I would often tell them that I would do an x-ray first. Usually, if you're coughing so badly, the cancer will be obvious on the x-ray. So, I might see something, and then we will go to a certain track.”
“But the main issue about cancer is this, a negative result actually doesn't mean you don’t have a small cancer or something that's hiding behind somewhere. If you really want to make sure there's no hint of cancer, I would suggest a low dose CT lung screening to clear the lungs structurally.” Dr. Ng adds. “I always look at the lung’s structure first before its function. You often can’t detect lung cancer early without a CT scan.”
Hence, if you have a lingering cough that doesn’t go away and tick off several risk factors of cancer such as smoking and a family history of the cancer, it is better to err on the side of caution and go for a CT scan to get your cough and lungs checked out.
According to Dr. Liu, the basic tenet of managing allergic rhinitis is understanding what is triggering the patient. This way, those suffering from allergic rhinitis will know what to avoid as well as receive a treatment plan catered to what they are allergic to.
Aside from an understanding of what triggers someone’s allergic rhinitis, Dr. Liu mentions that the severity of their condition is also important.
“We’ll have a baseline check of how severe the symptoms are and how we usually classify severity is by how often the symptoms occur and how severe are the occurrences: Do they affect the quality of life, like sleep? Do they miss school? That kind of thing. Then from there, we suggest treatment according to the severity,” says Dr. Liu.
With asthma, Dr. Ng recommends getting your symptoms checked out first if you are experiencing chest discomforts, coughing, and a lot of phlegm.
“First, you must be able to diagnose it. Once you diagnose the condition, it is about managing the triggers like allergic exposures or trying to get your vaccinations done to avoid infections and mask up in high-risk areas,” says Dr. Ng. “Asthma is a bit like a weighing scale. The more triggers you get, you’ll need to balance them with inhalers.”
“The idea is to get the condition diagnosed and then manage it appropriately.”
Allergic rhinitis and asthma are different conditions, but they have some similarities between them. What is important with regard to both the conditions is that, although they are chronic diseases, the right treatment and medication can help you manage their symptoms effectively.
