Asthma is not a single disease. It can have different characteristics (called “phenotypes”) and, as with many chronic conditions, it can differ from person to person.
Some of the most common phenotypes of asthma are:
- Allergic asthma
This is the most easily recognised asthma type. Symptoms can be triggered if you are exposed to things that you are allergic to, such as pollen, dust mites or pets, as well as other types of triggers. Allergic asthma often starts in childhood and may be associated with previous allergies or a family history of allergies. Reducing exposure to allergens may sometimes improve the control of allergic asthma.
- Non-allergic asthma
Some patients have asthma that is not associated with allergy. Symptoms may be triggered by viral infections, pollution, stress or other conditions.
- Adult-onset asthma
Asthma often starts during childhood. But, in some cases, particularly in women, it can present for the first time in adult life, even in people without a history of allergy. The exact causes of adult-onset asthma are not well understood. It sometimes occurs after a respiratory infection, or after occupational exposure to irritants or allergens, or it may be caused by a variety of agents including smoking, obesity, stressful life events, hormonal changes, or, in some patients, after starting medications such as beta-blockers (tablets or eye drops) or non-steroidal anti-inflammatory drugs.
- Asthma with persistent airflow limitation
Some patients with long-standing asthma develop airflow limitation. This means that the flow through the airways is limited, sometimes due to airway wall remodelling. This condition is persistent or incompletely reversible.
- Asthma with obesity
Some obese patients with asthma have prominent respiratory symptoms. In these patients, the type of inflammation differs from that of some other asthma types , with lower levels of eosinophils, which are a component of the immune system.
- Lacwik P., Kupczyk M. Asthma Phenotype Overlap: More May Be Less. J Allergy Clin Immunol Pract. 2021 Jan;9(1):363-364.