Asthma may be a disease with one name. But experts say unbeknown to most people who have it, it is not just one disease, nor is there a “one-size-fits-all” treatment. As detailed in a new 54-page set of guidelines developed by an expert panel, in the 13 years since the last guidelines were issued, tremendous progress has been made in understanding the causes and physiological effects of various kinds of asthma and the approaches needed to treat them and minimise flare-ups. The guidelines were published in the Journal of Allergy and Clinical Immunology.

“In recent years, we’ve recognised that everyone’s asthma is a little different, with different underlying mechanisms, and the paradigm for treating has changed completely,” said

Dr Michael Wechsler, an asthma specialist at National Jewish Health in Denver, US. Asthma is now recognised as a far more complex condition than experts realised in 1991 when the first comprehensive guidelines were issued. It is now considered a syndrome with many different characteristics, or phenotypes, that result from the interaction between a person’s genetics and environment.

The newest treatment with biologics is heralding personalised therapy for severe asthma not well-controlled by other, cheaper, remedies. Biologics are drugs, made from modified molecules from the cells of live organisms, designed to target specific disease pathways that culminate in asthma symptoms. “The last 13 years have seen an explosion of new strategies, concepts, understanding of mechanism, drugs and treatments,” Dr Wechsler said in an interview. “In just the last five years, five drugs have been approved for treating asthma.”

The new guidelines can be especially helpful for people being treated for asthma, mild or severe, that is now not adequately controlled. More than half of the patients are treated by primary care doctors, with referrals to pulmonologists or allergists when their condition is severe or doesn’t respond well to treatment, said Dr Michelle M. Cloutier, professor emerita, University of Connecticut School of Medicine, US, who chaired the panel.

Asthma is not an infection, although the body reacts as if an enemy had attacked it. It is a chronic disease in which airways become inflamed in response to triggering substances or behaviours. The airways swell and narrow and the muscles surrounding them tighten, causing a bronchospasm. Unless that is quickly reversed, it can become very difficult to breathe and result in hospitalisation or death.

Although people with asthma always have some degree of airway inflammation, they are particularly sensitive to certain factors that can make the inflammation worse. Thus, some people have environmental allergies — for example to pollen, animal dander, dust mites, rodents or cockroaches — that when encountered can trigger an attack. Others are sensitive to irritants such as tobacco smoke, air pollutants or strong odours.

For some , a viral infection, such as flu or common cold, or use of a medication such as aspirin, an NSAID or beta-blocker, can enhance inflammation and result in laboured breathing. Still others experience constricted airways when they exercise, especially in cold weather. Even strong emotions, such as fear, anger, excitement or laughter, and sudden changes in the weather are problems for some people with asthma.

Although several people feared they would be especially susceptible to contracting Covid-19, the evidence has not shown an increased risk either in contracting the coronavirus or developing a worse infection if they did, Dr Wechsler said. In fact, he added, “treating asthma may even protect against Covid.”

Researchers recognise that the triggering event of an attack can have different manifestations within the airways and therefore respond better to different treatments. In allergic asthma, the inflammatory cells eosinophils collect in the airways, but when a viral infection triggers the inflammation, neutrophils are released, warranting a different treatment.

The new guidelines highlight the value of a measurement called Feno or fractional exhaled nitric oxide, a biomarker described as useful in correctly diagnosing and adequately treating asthma in different patients. For children aged five and older, a nitric oxide measurement can help confirm the diagnosis and evaluate the effectiveness of treatment.

Although the guidelines do not provide hard-and-fast rules, they offer valuable treatment suggestions when currently used remedies do not result in the relief possible. For example, encasing mattresses and pillows in allergy-protective covers is not adequate for someone allergic to dust mites.

“Single-component interventions often do not work” in efforts to control indoor allergens. Among the combined approaches suggested were using pesticides against house-dust mites on carpets, mattresses and furniture; air-filtration systems and air purifiers; removal of wall-to-wall carpets and area rugs, at least in the allergic person’s bedroom; and mold mitigation.

The report also cautioned against relying on a negative result from an allergy test if the symptoms worsen when exposed to the allergen. On the other hand, some patients who test positive on an allergy test may not react to that substance in real life. Some may have developed a tolerance to the allergen that could be undone by attempts to reduce the patient’s exposure to it.

NYTNS