The risks and symptoms of household mold

Health experts caution that even mild but prolonged exposure to mold over several years can lead to significant respiratory problems. In extreme cases, a short but intense exposure may be enough to cause severe lung damage. However, early detection and removal of mold can prevent disease progression and protect lung health.

Dr. Avraham (Rami) Unterman, a pulmonary specialist at Ichilov Hospital in Tel Aviv, explained that mold exposure is linked to two primary lung conditions.

"The first is asthma," Unterman said. "Mold can trigger asthma attacks in those already diagnosed with the condition and even cause asthma to develop in people who have never had symptoms before."

"The second, and more serious, is chronic pneumonia caused by hypersensitivity to mold," he added. "This condition leads to persistent coughing and increasing difficulty in breathing, and if left untreated, it can progress to pulmonary fibrosis — a gradual scarring of lung tissue. In severe cases, it may even require a lung transplant."

Lung damage from mold exposure often goes unnoticed in its early stages, Unterman said. "The lungs have a high reserve capacity, so a person can lose up to 30% of lung function without experiencing symptoms," he explained. "Shortness of breath typically appears only after a significant portion of the lungs is no longer functioning properly."

People suffering from a chronic cough lasting more than three months should seek medical evaluation, he said.

"Anyone with a persistent cough should undergo a thorough check-up, including a lung function test, a chest X-ray and, if necessary, a CT scan," Unterman said. "While a chronic cough is often caused by conditions like asthma or chronic sinusitis, in some cases, it may indicate something more serious, such as pulmonary fibrosis or even lung cancer."

A persistent throat-clearing habit, though not considered a cough, may also indicate an underlying issue, he said. "Chronic postnasal drip or acid reflux are common causes, but if throat clearing is persistent, it’s worth investigating to rule out more serious conditions."

Not everyone exposed to mold will develop respiratory issues. "In a workplace or home with mold exposure, 100 people might be exposed, but only one might develop sensitivity," Unterman said.

Certain professions are at higher risk. "Bakers, for example, work in environments where flour can harbor mold spores," he said. "Farmers handling hay or working in damp barns are also at increased risk."

Mold can sometimes go unnoticed for long periods. "I once had a patient who was convinced she had never been exposed to mold," Unterman recalled. "Only after I pressed her to check thoroughly did she discover hidden mold behind a damp bedroom wall, which had spread to clothes stored in an adjacent closet. That exposure led to a severe lung disease."

In addition to mold, exposure to birds can also pose respiratory risks. "Bird feathers and droppings release airborne particles that may trigger an immune response in sensitive individuals," Unterman said. "I had a patient who kept dozens of canaries as a hobby, but the exposure nearly led him to require a lung transplant."

Pigeon droppings on balconies can also be hazardous, as can sleeping on feather pillows. Even environments with heated water, such as saunas and hot tubs, can harbor bacteria that may cause respiratory infections.

"Saunas and hot tubs are generally safe," Unterman said. "But if someone develops a chronic cough after exposure, they should get checked to rule out an infection."

"If the disease is mainly inflammatory, we prescribe anti-inflammatory treatments such as steroids," Unterman said. "If the primary issue is lung scarring, we use antifibrotic medications. Sometimes, we need to combine treatments, depending on the patient’s condition."

However, treatment success is not always guaranteed. "In some cases, pulmonary fibrosis progresses despite removing the exposure and providing medical treatment," he said. "At that stage, the disease almost takes on a life of its own."

Unterman emphasized that chronic pneumonia due to mold hypersensitivity is often underdiagnosed, even by specialists. "Many primary care doctors — and even some pulmonologists — are not familiar with this disease, which makes early detection difficult," he said. "Anyone with prolonged respiratory symptoms should get checked, because early intervention can make all the difference."

Dr. Avraham (Rami) Unterman is a pulmonary specialist and director of the Center of Excellence for Pulmonary Fibrosis at Tel Aviv Sourasky Medical Center.