Pulmonary Langerhans Cell Histiocytosis (PLCH): Symptoms, Causes, and Management

Some lung diseases may begin with nonspecific symptoms such as coughing, fatigue, or shortness of breath, making them easy to mistake for more common respiratory conditions. One rare condition worth knowing about is Pulmonary Langerhans Cell Histiocytosis (PLCH), a lung disease that is strongly associated with cigarette smoking, particularly in adults.

PLCH can cause small nodules and cyst-like spaces to develop within the lungs. As the disease progresses, these changes may affect lung function. Some people may also develop complications such as pneumothorax or pulmonary hypertension. Recognizing the symptoms and risk factors can help patients receive appropriate evaluation and care.

What Is Pulmonary Langerhans Cell Histiocytosis?

Pulmonary Langerhans Cell Histiocytosis, or PLCH, is a disease characterized by the abnormal accumulation and proliferation of cells with features of Langerhans cells around the small airways and within lung tissue. This process causes inflammation and can damage the structure of the lungs.

During the early stages, the disease may produce small nodules. As PLCH progresses, these nodules may develop into cavities or irregularly shaped cysts, and scarring of the lung tissue may occur.

Langerhans Cell Histiocytosis can also affect other parts of the body, including the bones, skin, lymph nodes, and pituitary gland. In adults, however, PLCH often occurs as a disease limited to the lungs.

Why Is PLCH Important?

PLCH is uncommon, and its early symptoms can resemble those of other respiratory diseases. Some people have no symptoms at all, and lung abnormalities may be discovered incidentally during a chest X-ray or CT scan performed for another reason.

If the disease progresses, however, it can damage lung tissue and reduce the lungs’ ability to exchange gases efficiently. An important complication is pneumothorax, or a collapsed lung, which can occur when a lung cyst ruptures and allows air to enter the space between the lung and chest wall. This may cause sudden chest pain and difficulty breathing.

People with more advanced disease may also develop pulmonary hypertension, and severe cases can eventually lead to respiratory failure.

Causes and Risk Factors of PLCH

The exact cause of PLCH is not yet completely understood, but the condition has a particularly strong association with cigarette smoking.

Most adults diagnosed with PLCH are current or former smokers. Substances in cigarette smoke are believed to stimulate inflammatory processes and promote the accumulation of Langerhans cells within the lungs. However, because PLCH does not develop in every smoker, other biological and genetic factors may also be involved.

Factors associated with PLCH include:

Cigarette smoking, particularly among young adults
Long-term exposure to inhaled smoke and related substances
Smoking cannabis or other inhaled substances, which specialists recommend avoiding in people with PLCH
Vaping or using other products that deliver inhaled substances into the lungs, which should be stopped in people diagnosed with PLCH

PLCH most commonly affects adults between approximately 20 and 40 years of age, although it can occur at other ages.

Symptoms to Watch For

The symptoms of PLCH vary considerably from person to person. Some individuals have no symptoms, while others experience persistent respiratory problems.

Possible symptoms include:

Cough, often a dry cough
Shortness of breath or becoming easily breathless, particularly during physical activity
Chest pain, especially pain associated with breathing
Fatigue
Unintentional weight loss
Fever in some patients
Coughing up blood, although this does not occur in everyone

For some people, the first sign of PLCH may be a sudden pneumothorax, resulting in acute chest pain and difficulty breathing.

If Langerhans Cell Histiocytosis affects organs outside the lungs, additional symptoms may occur, such as bone pain, skin rashes, or excessive urination caused by hormone abnormalities related to pituitary gland involvement.

When Should You Seek Emergency Medical Care?

People with PLCH or those at increased risk should pay particular attention to symptoms that develop suddenly, including:

Sudden chest pain, particularly on one side
Sudden or rapidly worsening shortness of breath
Difficulty breathing even while resting
Bluish or unusually dark discoloration of the lips or fingertips
Coughing up blood
Dizziness, fainting, or weakness accompanied by difficulty breathing

Sudden chest pain and shortness of breath may indicate pneumothorax and require prompt medical evaluation at a hospital.

How Is PLCH Diagnosed?

Diagnosing PLCH involves several types of information. A doctor will usually ask about symptoms, smoking history, and exposure to inhaled substances, as well as perform a physical examination and assess respiratory function.

One of the most important tests is high-resolution computed tomography (HRCT) of the chest. HRCT can reveal patterns of nodules and cysts associated with PLCH. These abnormalities often predominantly affect the upper and middle regions of the lungs.

A pulmonary function test may also be performed to evaluate how well the lungs work and exchange gases. The pattern of abnormalities can vary between patients, and the lung’s ability to transfer gases may be reduced.

If the medical history and CT findings are insufficient to establish the diagnosis, a doctor may consider bronchoscopy, bronchoalveolar lavage, or a lung biopsy for pathological examination.

Because other lung diseases can produce similar imaging findings, PLCH should be evaluated by an appropriate medical specialist.

Treatment and Management

The management of PLCH depends on the severity of the disease, the patient’s symptoms, lung function, whether other organs are involved, and how the disease progresses over time.

For people with PLCH who smoke, the most important intervention is smoking cessation. Patients should also avoid vaping, cannabis, and other substances that are inhaled into the lungs.

In some patients, smoking cessation alone may result in improvement of lung abnormalities or stabilization of the disease. Nevertheless, continued medical follow-up remains important because PLCH can progress even after smoking has stopped.

If symptoms persist, lung function deteriorates, or the disease continues to progress, doctors may consider systemic therapy depending on the individual case. Certain medications, such as cladribine, have been used in selected patients, but treatment decisions should be made under the supervision of specialists experienced in managing PLCH.

For patients with severe disease resulting in respiratory failure that does not respond adequately to other treatments, lung transplantation may be considered in selected cases.

How to Take Care of Yourself

Protecting lung health and reducing exposure to potential triggers are important parts of PLCH management.

Stop smoking and avoid secondhand smoke

Smoking cessation is a central part of PLCH management. People who have difficulty quitting can seek support from doctors or other healthcare professionals to develop an appropriate smoking cessation plan.

Avoid substances that may irritate the lungs

People with PLCH should avoid vaping, cannabis, smoke, and other substances that are inhaled into the respiratory system. Exposure to irritating dust or chemicals should also be reduced whenever possible.

Attend regular lung function follow-ups

Doctors may recommend periodic pulmonary function tests or imaging studies to determine whether the disease is stable, improving, or progressing.

Reduce the risk of respiratory infections

Patients should maintain their general health, avoid exposure to people with respiratory infections when appropriate, and discuss recommended vaccinations with their healthcare provider based on their age, medical conditions, and overall health.

Exercise appropriately

Regular physical activity at a level appropriate for the individual’s lung function may support overall health. People who experience significant breathlessness or have advanced lung disease should consult their doctor before increasing the intensity of exercise.

Who Should Consult a Doctor?

Medical evaluation is recommended for people with persistent coughing or difficulty breathing, particularly those with a history of smoking. Consultation is also important for people who:

Experience progressively worsening shortness of breath
Have had an unexplained pneumothorax, especially if it has occurred more than once
Have nodules or cysts detected on a chest X-ray or CT scan
Have already been diagnosed with PLCH and notice new or worsening symptoms
Develop symptoms outside the respiratory system, such as bone pain, skin rashes, or excessive urination
Need assistance with smoking cessation

Appropriate diagnosis and regular follow-up are important because the course of PLCH can vary significantly from one person to another.

Summary

Pulmonary Langerhans Cell Histiocytosis, or PLCH, is a rare lung disease characterized by the abnormal accumulation and proliferation of Langerhans cells in the lungs. This can lead to inflammation, nodules, cyst formation, and damage to lung tissue. The disease is strongly associated with cigarette smoking, particularly among young adults.

Common symptoms include cough, shortness of breath, fatigue, and chest pain, although some patients may have no symptoms. One important complication is pneumothorax, which may cause sudden chest pain and difficulty breathing.

Stopping smoking and avoiding inhaled substances are central to the management of PLCH, and patients should undergo appropriate medical follow-up to monitor lung function. Anyone who develops sudden chest pain or acute difficulty breathing should seek immediate medical attention.

Prepared by: Poonyanuch Angkanawin, Pharm.D.

Pulmonary Langerhans Cell Histiocytosis (PLCH): Symptoms, Causes, and Treatment