Yes, a small pneumothorax can heal on its own. Your body naturally reabsorbs the trapped air from around the lung at a rate of about 1.25% to 2% of the pneumothorax volume per day when breathing normal room air. That means a small collapse could take several weeks to fully resolve without any procedure, but it does happen routinely under medical observation.
Whether yours qualifies for this watch-and-wait approach depends on the size of the collapse, what caused it, and how stable your breathing and circulation are.
What “Small Enough to Heal” Actually Means
The key measurement is the distance between the edge of your collapsed lung and the inside of your chest wall on an X-ray or CT scan. The British Thoracic Society considers a pneumothorax “small” when that gap is less than 2 cm. If you fall into that category and your vital signs are stable, conservative management (observation without a chest tube or needle) is a reasonable first option.
Not every guideline agrees on the cutoff. American guidelines tend to lean toward intervention regardless of size. But the overall trend in recent years has shifted toward less invasive management for stable patients, with the 2023 BTS guideline recommending that ambulatory (outpatient) management be considered as a first-line approach for primary spontaneous pneumothorax in adults who have good support at home and access to follow-up care.
How Your Body Reabsorbs the Air
The pleural space around your lungs normally contains only a thin film of fluid. When air leaks in, your body starts absorbing it back into the bloodstream through the tiny blood vessels lining the pleura. On room air, this happens at roughly 2% of the pneumothorax per day.
Supplemental oxygen speeds this process significantly. Breathing high-flow oxygen essentially flushes nitrogen out of your blood, which creates a steeper pressure gradient that pulls nitrogen from the trapped air pocket back into circulation faster. Studies show this roughly doubles the daily resolution rate, from about 2% per day to over 4% per day. Some older estimates put it even higher, describing a nearly fourfold increase in reabsorption speed. For a small pneumothorax, this can shave days or even a week off recovery.
Primary vs. Secondary Pneumothorax
The type of pneumothorax matters enormously for whether self-healing is realistic.
A primary spontaneous pneumothorax happens in someone with no known lung disease, typically tall, thin young men in their teens or twenties. Small blebs on the lung surface rupture for reasons that aren’t fully understood. These are the best candidates for conservative management because the underlying lung tissue is healthy and the leak usually seals itself.
A secondary spontaneous pneumothorax occurs in someone who already has lung disease like COPD, cystic fibrosis, or severe asthma. These are trickier. No large prospective studies have tested conservative management for secondary pneumothorax head-to-head against intervention, and doctors are generally more cautious because diseased lungs have less reserve. That said, it’s not impossible. A retrospective study found that 25 secondary pneumothoraces larger than 1 cm were successfully managed conservatively. When persistent air leaks developed in secondary cases, 61% resolved within seven days and 81% resolved by 14 days without further intervention. Still, the threshold for placing a chest drain is lower when underlying lung disease is present.
What Observation Looks Like
Conservative management doesn’t mean you go home and forget about it. Typically you’ll be monitored in an emergency department or observation unit for several hours to confirm the pneumothorax isn’t expanding. A repeat X-ray checks that things are stable or improving. If you’re breathing comfortably and your oxygen levels are normal, you may be discharged with instructions to return for follow-up imaging, usually within 24 to 48 hours and again at one to two weeks.
Some centers now use ambulatory management, where you go home with close follow-up rather than being admitted. The 2023 BTS guideline endorses this approach when the right infrastructure exists. You’ll be given clear instructions on what warning signs to watch for. The goal is to let your body do the work while keeping you safe.
Warning Signs That Need Immediate Attention
A simple pneumothorax can, in rare cases, progress to a tension pneumothorax, where air continues leaking in but can’t escape. This compresses the heart and major blood vessels, and it’s a life-threatening emergency. During observation at home, you should go to the emergency room immediately if you experience sudden worsening shortness of breath, rapid heart rate, chest pain that intensifies, or if you feel lightheaded or faint. Visible signs include the skin turning bluish (especially around the lips), veins in the neck becoming swollen and distended, or a sense that breathing is getting harder rather than easier over time.
Recurrence Risk After Healing
One of the realities of letting a pneumothorax heal on its own is that the underlying vulnerability, those small blebs on the lung surface, often remains. In a study of 253 patients who were not initially treated with surgery, about half experienced a recurrence at some point. Of those who did recur, 37% had their second episode within the first year. That’s a significant number, and it’s part of why surgery is sometimes discussed even after a first episode, particularly for people in high-risk occupations like pilots or commercial divers.
Surgery to prevent recurrence typically involves removing visible blebs and roughening or sealing the pleural surfaces so the lung adheres to the chest wall. This dramatically lowers the recurrence rate but is usually reserved for second episodes or specific circumstances.
Flying and Diving After Recovery
Air expands at lower pressures, so flying in a commercial aircraft cabin (pressurized to the equivalent of about 6,000 to 8,000 feet elevation) poses a real risk if any trapped air remains. Most medical societies recommend waiting 7 to 14 days after a follow-up X-ray confirms the pneumothorax has fully resolved before boarding a flight. Some emerging evidence suggests shorter waits may be safe for very small, stable cases, but the two-week recommendation remains standard.
Scuba diving is a different situation entirely. A history of spontaneous pneumothorax is considered an absolute and permanent contraindication for diving. The pressure changes underwater are far more extreme than in an airplane, and the risk of a catastrophic recurrence is too high. The only potential exception is if you undergo bilateral surgical pleurectomy with removal of all visible blebs, followed by a clear high-resolution CT scan and normal lung function tests. Even then, the decision involves careful specialist evaluation.