Histoplasmosis is a fungal infection that can cause swelling, inflammation, and, sometimes, small semi-opaque or calcified nodules on the lungs. However, histoplasmosis does not always cause symptoms.

Many people with histoplasmosis do not experience symptoms. However, the fungal infection may still leave small scars on their lungs.

People develop histoplasmosis when they inhale the spores of Histoplasma capsulatum, a fungus that thrives in soil enriched with bird or bat droppings.

Histoplasmosis is most common in the eastern and central regions of the United States, especially in areas near the Ohio and Mississippi River valleys.

This article contains pictures of histoplasmosis in the lungs, explains how the fungal infection affects the lungs, identifies which people are most vulnerable to severe cases of histoplasmosis, and when to contact a doctor.

When diagnosing histoplasmosis, doctors may use CT scans, PET scans, or X-rays to look for certain signs, such as nodules on the lungs and inflammation.

However, imaging can only lead a doctor to diagnose pulmonary fungal disease. They cannot confirm histoplasmosis without a medical history and further laboratory tests or a biopsy of an area of inflammation.

These pictures show how histoplasmosis can present in the lungs.

When visible in the lungs, histoplasmosis may appear as pneumonitis, hilar lymphadenopathy, or granulomas.

A chest X-ray can identify pneumonitis, which is inflammation of the lungs, and hilar lymphadenopathy, which is swollen lymph nodes near the lungs’ nerves and blood vessels.

Granulomas may appear more clearly on a CT scan, providing a more detailed image than an X-ray.

Granulomas are noncancerous nodules or clumps of white blood cells and other tissue that form when the spores of H. capsulatum enter the lungs. Granulomas aim to contain the fungal infection and stop it from spreading.

The nodules may be round- or oval-shaped, either spread throughout the lungs or clumped closely together, and can be as small as 1–2 millimeters (mm) in diameter.

Some granulomas have a low-density center, meaning the center appears hazy and does not obscure the pulmonary vessels or other bronchial structures underneath.

Other nodules have a dense center surrounded by a thin rim of calcification.

Learn more about other types of nodules in the body.

Mild, acute cases of histoplasmosis may not cause any symptoms or may cause flu-like symptoms such as:

According to the Centers for Disease Control and Protection (CDC), symptoms typically appear 3–17 days after exposure and clear up within a month.

However, histoplasmosis may become severe if a person experiences heavy exposure to the fungus or already has a weakened immune system.

For example, chronic cavitary pulmonary histoplasmosis (CPH) may occur in people with respiratory-related conditions, such as emphysema or chronic obstructive pulmonary disease (COPD).

Histoplasmosis at this stage typically causes milder symptoms than acute histoplasmosis, but the symptoms can last for months or years and cause progressively worsening lung damage.

People who are severely immunocompromised, such as people with advanced HIV, are at a greater risk of developing progressive disseminated histoplasmosis (PDH).

This is when histoplasmosis spreads from the lungs to other body parts and can cause complications such as:

Learn how HIV affects the body.

Because most cases of histoplasmosis go undetected or cause mild symptoms and then clear up on their own, many people with histoplasmosis do not seek medical treatment.

However, the American Lung Association (ALA) recommends a person contact their doctor if they develop symptoms of a respiratory infection and live in an area where histoplasmosis infection rates are high — especially if the person has a weakened immune system.

After someone receives a histoplasmosis diagnosis, they can talk with their doctor about:

  • how histoplasmosis may affect their lungs
  • potential treatments and side effects of treatments
  • managing histoplasmosis with any other pre-existing conditions
  • any necessary precautions during recovery
  • ways to prevent additional histoplasmosis infections

Learn how doctors can diagnose histoplasmosis.

This section answers some frequently asked questions about histoplasmosis in the lungs.

How long does it take to heal histoplasmosis in your lungs?

Most acute cases of histoplasmosis heal on their own within a month.

When symptoms last longer, doctors typically recommend a 3-month course of itraconazole, a standard prescription antifungal medication.

That time increases to 6 months and 1 year for people with CPH and PDH, respectively.

Histoplasmosis can be complex and can develop into granulomas. If that does occur, a person may not require treatment. However, a discussion with a specialist can help determine this.

What does histoplasmosis do to the lungs?

Histoplasmosis can cause inflammation and swelling throughout the lungs, which may lead to bronchitis or pneumonia.

Even if a person is asymptomatic, or has no symptoms, histoplasmosis can leave small spots or scars on their lungs.

Does histoplasmosis cause lung nodules?

Yes, histoplasmosis may cause small lung nodules called granulomas.

These granulomas are benign, or noncancerous, clumps of white blood cells that form to block the spread of the fungal infection.

Does a chest X-ray show histoplasmosis?

A chest X-ray may highlight some visual symptoms of histoplasmosis in the lungs, such as lung tissue inflammation and lymph node swelling.

Some chest X-rays may capture images of granulomas as well, but the images may not be clear enough to differentiate between histoplasmosis and other conditions, such as cancer.

So, doctors may use other types of diagnostic radiology exams, specifically CT scans, to get more detailed images of the lungs.

However, even those images may show nodules with characteristics similar to lung cancer. At this point, doctors may use other diagnostic tests that examine the person’s urine, blood, or tissues for signs the fungus is present.

Histoplasmosis is a fungal infection that affects a person’s lungs. It can cause flu-like symptoms, such as fever, chills, and body aches.

Histoplasmosis can cause swelling and inflammation of the lungs and lymph nodes and cause the lungs to develop small, benign nodules called granulomas.

Even someone who is asymptomatic may still develop small scars or spots on their lungs.

Histoplasmosis can be mild and often clears up within 1 month without treatment. However, people with weakened immune systems or other respiratory conditions, such as emphysema, have a significant risk of developing severe histoplasmosis and should consider talking with their doctor.