Nasal congestion¹（鼻塞，鼻充血） can be a sign of severe asthma²（哮喘） , which means that healthcare professionals should be extra vigilant³（警惕的） when it comes to nasal complaints. Furthermore, more severe asthma appears to be more common than previously⁴ thought, reveals a study from the Sahlgrenska Academy's Krefting Research Centre. Published in the online scientific journal Respiratory Research, the population study included 30,000 randomly⁵ selected participants from the west of Sweden and asked questions about different aspects of health.

"This is the first time that the prevalence of severe asthma has been estimated in a population study, documenting that approximately 2% of the population in the West Sweden is showing signs of severe asthma," says Jan Lötvall, one of the authors of the study and professor at the Sahlgrenska Academy's Krefting Research Centre. "This argues that more severe forms of asthma are far more common than previously believed, and that healthcare professionals should pay extra attention to patients with such symptoms.

"We also found that more pronounced nasal symptoms, such as chronic⁶ rhinosinusitis（鼻窦炎） , in other words nasal congestion and a runny nose（流鼻涕） for a long period of time, can be linked to more severe asthma."

Jan Lötvall suggests that patients who report nasal complaints, perhaps together with minor⁷ symptoms from the lower respiratory tract⁸（呼吸道） , such as wheezing⁹, shortness of breath during physical effort, and night-time awakings because of breathing problems – should be investigated for asthma.

"These findings suggest that some parts of the immune system that are activated¹⁰ in connection with chronic nasal problems might be linked to severe asthma, and this insight could lead to new forms of treatment in the long run," says Lötvall. "Effective treatment for troublesome nasal and sinus complaints could, in theory, reduce the risk of severe asthma, though this is something that needs further research."

These results increase our understanding of the factors that play a role in severe asthma, and could help clinical researchers to understand which mechanisms¹¹ lead to more severe asthma. At the same time, Lötvall believes that healthcare professionals should be aware of the possibility of severe asthma in patients showing signs of nasal problems, such as congestion, polyps（息肉） and a poor sense of smell.