Adult-Onset Asthma: What Triggers It and How Is It Diagnosed?

Adult-onset asthma is asthma that first appears after childhood, often with wheezing, cough, chest tightness or shortness of breath that comes and goes. Several factors can contribute, including allergens, respiratory infections, workplace exposures, smoking, hormonal changes and reflux. Clinicians diagnose it by combining your history, a physical exam and breathing tests such as spirometry. This article covers triggers, the diagnostic process, conditions that look similar, and the symptoms that need emergency care.

What adult-onset asthma is and how it can start

Asthma is a long-term condition in which the airways become inflamed and narrow, and the muscles around them can tighten. According to MedlinePlus, this can cause wheezing, coughing, chest tightness and trouble breathing. Many people think of asthma as a childhood illness, but it can begin in your 30s, 50s, 70s or later.

Some adults had mild childhood asthma that went quiet and returned. Others have no earlier history at all. Researchers describe asthma as a group of related conditions rather than a single disease, and the exact mechanism behind new asthma in adults is not fully understood. Genes, allergies, the environment and the immune system all appear to play a part, as discussed in a review of genetics and epigenetics in asthma.

Common symptoms in adults

Symptoms can vary from person to person and from week to week. Many adults notice:

• Wheezing, a whistling or squeaky sound when breathing out
• A cough that is worse at night or early in the morning
• Chest tightness or pressure
• Shortness of breath with exertion, cold air or strong smells
• A cold that settles in the chest and lingers

Because these symptoms overlap with other conditions, adult asthma is sometimes mistaken for a slow-to-clear chest infection, ordinary aging or being out of shape. A cough that keeps returning is worth mentioning to a clinician.

What may trigger adult-onset asthma

A trigger is something that can start or worsen symptoms. Triggers differ between people, and for many adults more than one factor is involved.

Allergens

Pollen, dust mites, mold, pet dander and cockroach droppings can inflame the airways in people who are sensitized to them. Allergies and asthma often occur together. MedlinePlus explains how the immune system reacts to substances that are usually harmless. Moving to a new home, getting a pet or a water-damaged space can introduce a new allergen.

Respiratory infections

Colds, flu and other viral infections can inflame the airways, and in some adults a respiratory illness appears to be followed by lasting asthma symptoms. Viruses are also a recognized cause of flare-ups in people who already have asthma, as reviewed in a paper on asthma exacerbation and airway infection. Flu itself is covered on MedlinePlus.

Workplace exposures

Some adults develop asthma from substances breathed in at work, such as cleaning products, fumes, dusts, flour, latex or chemicals used in manufacturing. A helpful clue is symptoms that improve on weekends or vacations and return on workdays. Tell your clinician about your job and the products you handle so they can consider this possibility.

Smoking, vaping and air irritants

Tobacco smoke, secondhand smoke, wildfire smoke and air pollution can irritate the airways. Smoking can also make asthma harder to control. MedlinePlus offers information on quitting, and a clinician can discuss options that fit you.

Hormonal and body changes

Some women notice new or worsening asthma around pregnancy, menstrual cycles or menopause, though the reasons are not fully clear. Weight gain and obesity are also associated with asthma in adults.

Reflux, medicines and other factors

Acid reflux is common in people with asthma and may contribute to cough and symptoms for some. If heartburn is part of your picture, see our guide to GERD. Certain medicines, including aspirin and other NSAIDs in some people, as well as some beta blockers, can worsen asthma. Do not stop a prescribed medicine on your own. Ask your prescriber or pharmacist whether any of your medicines could be a factor. Exercise, cold air, strong odors and emotional stress can also set off symptoms.

How adult-onset asthma is diagnosed

There is no single test that settles the question for everyone. Clinicians combine your history, an examination and breathing tests, and they consider other possible explanations.

History and exam

Expect questions about when symptoms happen, what seems to set them off, your work and home environment, allergies, smoking, reflux, family history and medicines. Your clinician will listen to your lungs, although they may sound normal between episodes.

Spirometry

Spirometry measures how much air you can blow out and how fast. In asthma, airflow is often reduced but can improve after you inhale a bronchodilator, a medicine that opens the airways. Your clinician may repeat the test on another day, because results can be normal when you are feeling well.

Other tests your clinician may consider

• Peak flow readings at home over a period your clinician specifies
• A bronchoprovocation (challenge) test when spirometry is normal but suspicion remains
• Allergy testing by skin or blood
• Blood tests, including eosinophil counts, which are discussed in our article on high eosinophils
• A chest X-ray to look for other causes of symptoms

Conditions that can look like adult-onset asthma

Several conditions share symptoms, and some people have more than one. Part of diagnosis is sorting these out.

• COPD is more common in older adults with a smoking history and involves airflow limitation that is not fully reversible. See COPD: Causes, Symptoms, and Management and MedlinePlus on COPD. Some people have features of both.
• Bronchitis or pneumonia can cause cough and breathlessness. Our guide on bronchitis or pneumonia explains how those differ.
• Heart conditions such as heart failure can cause wheeze and breathlessness, particularly when lying flat.
• Vocal cord dysfunction, chronic reflux cough and postnasal drip can also mimic asthma.

Because the list is long, a new wheeze or ongoing cough deserves a proper evaluation instead of self-treatment with leftover inhalers.

Treatment and long-term management

Asthma treatment usually has two parts: medicines that calm airway inflammation over time and medicines that relieve symptoms quickly. Which ones fit you depends on how often symptoms occur and how severe they are. A systematic review of guideline-driven asthma management describes this stepwise approach. For how the two types of inhaler differ, see controller vs. rescue inhalers and albuterol inhalers.

Inhaled medicines carry label cautions, and side effects such as a fast heartbeat or tremor can occur with quick-relief inhalers. Do not change the dose or timing of a prescribed inhaler on your own; ask the prescriber or pharmacist if something is not working or causes side effects.

Other steps that may help include:

• Working with your clinician on a written asthma action plan
• Learning and rechecking inhaler technique with a pharmacist or clinician
• Reducing exposure to your identified triggers
• Discussing vaccines, such as the flu vaccine, with your clinician
• Seeking help to quit smoking if you smoke

Living with adult-onset asthma

For many adults, symptoms can be controlled well with appropriate treatment and follow-up, though outcomes vary. Keep a simple symptom diary noting night waking, rescue inhaler use and possible triggers, and bring it to visits. If you need your quick-relief inhaler more often than usual, tell your clinician so they can decide whether your plan needs adjusting.

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