Fungal lung infections typically cause a cough, fever, shortness of breath, and fatigue that can easily be mistaken for bacterial or viral pneumonia. The overlap is so common that fungal pneumonias are often misdiagnosed, and many people only get the right diagnosis after antibiotics fail to help. Knowing the specific symptom patterns, especially the ones that set fungal infections apart, can help you recognize what’s going on sooner.
Symptoms Shared Across Most Fungal Lung Infections
Regardless of which fungus is involved, the core symptoms tend to look the same:
- Cough that persists for weeks, sometimes producing blood or mucus
- Fever and chills
- Shortness of breath
- Chest pain
- Fatigue
These symptoms mirror what you’d expect from a bacterial pneumonia, which is exactly the problem. Valley fever, histoplasmosis, and blastomycosis all present similarly to bacterial and viral pneumonia, so healthcare providers usually prescribe antibiotics first. When those antibiotics don’t work and symptoms persist or worsen, fungal infection becomes a leading suspect.
Histoplasmosis
Histoplasmosis comes from breathing in fungal spores found in soil, particularly soil contaminated with bird or bat droppings. It’s common in the Ohio and Mississippi River valleys. Most people who inhale the spores never get sick at all. Those who do develop symptoms typically notice them 3 to 17 days after exposure.
The symptoms include fever, cough, chills, headache, chest pain, body aches, and extreme tiredness. In mild cases, it can feel like a flu that just won’t quit. Chronic histoplasmosis, which is more common in people with existing lung disease, can drag on for months with worsening cough, weight loss, and shortness of breath.
Valley Fever (Coccidioidomycosis)
Valley fever is concentrated in the desert Southwest of the United States and parts of Mexico and Central America. What makes it distinctive is a set of symptoms you wouldn’t normally associate with a lung infection: joint pain (especially in the ankles, knees, and wrists), a rash, and deep tiredness that can linger long after the respiratory symptoms improve.
The respiratory symptoms themselves, including cough, fever, and shortness of breath, are standard. But if you’ve recently been in an endemic area and you’re dealing with painful, swollen joints alongside a cough, Valley fever is worth considering. In severe cases the infection can spread beyond the lungs to the bones, skin, and joints, causing painful sores and nodules that are more serious than the initial rash.
Blastomycosis
Blastomycosis is found in moist soil near waterways and decaying wood, primarily in the Great Lakes region and the Ohio and Mississippi River valleys. Its symptoms include fever, cough, shortness of breath, night sweats, muscle aches, joint and back pain, weight loss, and fatigue.
The distinguishing feature of blastomycosis is its tendency to involve the skin. Some people develop raised bumps, blisters, or ulcers on the skin even while the infection is primarily in the lungs. Severe cases can spread to bones, joints, and the central nervous system.
Aspergillosis
Aspergillosis behaves differently depending on your immune system and lung health. It comes in several forms, each with its own symptom profile.
Allergic Bronchopulmonary Aspergillosis (ABPA)
This is an allergic reaction to the fungus rather than a true infection. It primarily affects people with asthma or cystic fibrosis. The hallmark symptoms are wheezing, shortness of breath, and a cough that may bring up blood or mucus. It often looks like worsening asthma. Fever is rare.
Aspergilloma (Fungus Ball)
When Aspergillus spores settle into an existing cavity in the lung, often left behind by tuberculosis or another prior illness, they can grow into a dense mass called a fungus ball. The most notable symptom is coughing up blood, which can range from blood-streaked mucus to significant bleeding. Fatigue, shortness of breath, unintentional weight loss, and wheezing round out the picture.
Invasive Aspergillosis
This is the most dangerous form and almost exclusively affects people with severely weakened immune systems, such as organ transplant recipients or people undergoing chemotherapy. Symptoms come on faster and are more severe: high fever, chest pain, cough with blood, shortness of breath, and chills. It can spread to other organs, sometimes causing headaches, eye symptoms, skin lesions, and joint pain.
Pneumocystis Pneumonia (PCP)
PCP affects people with compromised immune systems, particularly those with untreated HIV/AIDS. Unlike other fungal lung infections that can hit otherwise healthy people, PCP is almost exclusively a disease of immune suppression. Symptoms develop over days to weeks and include fever, a dry cough, trouble breathing, chest pain, chills, and fatigue. The shortness of breath tends to get progressively worse, especially with physical activity, and can become severe.
How Fungal Pneumonia Differs From Bacterial
The symptoms alone won’t reliably tell you whether your pneumonia is fungal or bacterial. The real clues come from context. Where you live or have recently traveled matters enormously, since many fungal infections cluster in specific geographic regions. Your immune status matters too: people on immunosuppressive medications, those with HIV, and organ transplant recipients face a much higher risk of fungal pneumonia.
The single biggest red flag for an undiagnosed fungal infection is pneumonia that doesn’t respond to antibiotics. Antibiotics treat bacteria, not fungi. If you’ve completed a course of antibiotics and your cough, fever, and breathing problems haven’t improved or have gotten worse, a fungal cause is a real possibility. The American Lung Association specifically flags this scenario as one where testing for fungal pneumonia should be the next step.
Symptoms That Suggest the Infection Has Spread
Most fungal lung infections stay in the lungs, especially in people with healthy immune systems. But when the infection disseminates, meaning it spreads through the bloodstream to other parts of the body, new symptoms appear that have nothing to do with breathing.
Skin changes are among the most common signs of spread. These can include raised bumps, blisters, ulcers, or nodules. Joint and bone pain, particularly in the knees, ankles, and spine, can signal that the infection has reached the skeletal system. Headaches, confusion, or vision changes may indicate involvement of the brain or nervous system. Unintentional weight loss and drenching night sweats often accompany disseminated disease and reflect the body struggling to fight a widespread infection.
Disseminated fungal infections are far more common in people with weakened immune systems, but they can occasionally occur in otherwise healthy individuals, particularly with blastomycosis and coccidioidomycosis.