Can You Have Pneumonia Without a Fever?

Pneumonia is an infection of the lungs caused by bacteria, fungi, or viruses (including COVID-19). Fever is a common symptom of pneumonia. However, in certain rare cases some people have pneumonia without fever or with only a very mild form of it.

Several factors predispose people to develop pneumonia without fever: being very young (under age 2), being older than 65, or having a compromised immune system. It can also occur in cases of a milder form of the disease, called “walking pneumonia.”

Varying a great deal in terms of severity, pneumonia causes breathing difficulties, congestion, the production of mucus, and many other symptoms. The absence of fever in pneumonia does not necessarily indicate the infection is not severe or shouldn’t be taken seriously, which is why it’s important to understand this rare aspect of the condition.

What Is Pneumonia?

Pneumonia is a viral, bacterial, or fungal infection of one or both lungs. Physiologically, the infection inflames the air sacs (alveoli) of the lungs as white blood cells attack the invading bacterium, virus, or fungus in the body. The infection causes a buildup of pus and fluid in the air sacs, making you cough up phlegm and have difficulty breathing.

While pneumonia can affect people of any age or gender, it more often arises and is generally more severe in those who have weaker immune systems. This is why older people and younger children are most susceptible.

It’s also why pneumonia is of particular concern for people with chronic diseases like human immunodeficiency virus (HIV/AIDS), cancer, or other underlying conditions, as well as those undergoing significant surgeries.

Symptoms of Pneumonia

What makes pneumonia sometimes difficult to treat is that it has some of the same symptoms as the common cold or influenza (the flu). The signs of pneumonia typically include:

• Fever
• Chills
• Cough
• Thick, colored phlegm
• Shortness of breath
• Pain while breathing or coughing
• Headache
• Nausea and/or vomiting
• Diarrhea

The severity of symptoms depends on a person’s health status; pneumonia is much tougher to manage and presents with more severe symptoms in those who are immunocompromised or have underlying lung conditions.   

Symptoms can be age specific. Pneumonia in older adults (those over 65) and some immunocompromised patients, for instance, may be accompanied by confusion. Infants and toddlers under the age of 2 may experience breathing difficulties, feeding problems, a bluish tint to the skin or lips, fussiness, and less urine production.

Pneumonia Without Fever

Fever is not a disease in itself; rather, it’s a physiological response to illness. In fever, basically, the body raises its own temperature to help kill pathogens and fight infection. As such, pneumonia without fever tends to represent a reduced immune response. Immunity tends to be weaker in certain groups of the population, including:

• Adults age 65 or older
• Pregnant people
• Newborns, especially those born prematurely
• Infants and toddlers younger than 2

Further, a range of other conditions can impact immunity, including:

• Human immunodeficiency virus (HIV/AIDs)
• Cancer treatment with chemotherapy
• Taking certain medications like corticosteroids or others that suppress immune function
• Autoimmune disorders, including lupus, multiple sclerosis, and rheumatoid arthritis
• Having had an organ or bone transplant
• Drug, alcohol, or tobacco use
• Exposure to dust, chemical fumes, or secondhand smoke

Pneumonia without fever is also more likely in those with heart or lung conditions, including:

• Cystic fibrosis
• Asthma
• Chronic obstructive pulmonary disease (COPD)
• Emphysema
• Bronchiectasis
• Unmanaged diabetes
• Dementia
• Stroke

Additionally, those who develop “walking pneumonia,” a common form of pneumonia caused by infection from the Mycoplasma pneumoniae bacteria, may experience absent or severely reduced fever. Walking pneumonia is mild and highly treatable, rarely requiring hospitalization.

What’s important to remember about pneumonia without fever is that it still has the potential to be dangerous. In fact, it often arises precisely because the patient is already sick or more susceptible to illness in general. Symptoms range in intensity—from being mild to very severe. Be mindful of how you’re feeling, and don’t be afraid to call for help if symptoms worsen.

Complications

While most cases of pneumonia can be effectively managed, if the disease is allowed to progress, it can be particularly dangerous. What can happen? Here’s a quick breakdown:

• Respiratory failure: Severe inflammation and fluid buildup within the lungs can lead to very serious breathing difficulties, especially in those who already have lung conditions like asthma or COPD. Respiratory failure can become serious, requiring emergency care.
• Lung abscess: This is the accumulation of pus—a yellowish or green, thick fluid—in the cavities of the lung. Lung abscesses need to be drained, and in some cases, they have to be surgically removed.
• Bacteremia: This is the spread of pneumonia-causing bacteria to the bloodstream, which can become particularly problematic. Bacteria can spread to other organs, leading to dangerous conditions like kidney failure and meningitis (an infection of the fluid surrounding the brain and spine), among others.
• Pleural effusion: The tissue that lines the chest cavity and surrounds the lungs can become diseased or inflamed, causing the lungs to fill with fluid. This “water in the lungs” can seriously impact breathing. It’s treated by draining the fluid using a catheter or chest tube, with surgery sometimes necessary.

Diagnosis

Because pneumonia causes symptoms similar to other diseases, proper diagnosis is often a two-stage process. Healthcare providers need to ascertain the cause of the condition and test whether it’s bacterial, viral, or fungal in origin.  

A diagnosis may involve the following:

• Evaluation and assessment of health status is the first step. The practitioner will look at your medical history, assess current symptoms, and perform a physical examination. An important early step is listening to your lungs with a stethoscope.
• Chest X-rays can reveal how much fluid is in the lungs and the pattern of inflammation. This allows clinicians to understand how severe and advanced your case is.
• Blood tests determine how well your immune system is fighting pneumonia. Typically a complete blood count (CBC), which measures levels of all three blood cell types (red cells, white cells, and platelets), is ordered.
• A blood culture may also be performed. This can detect whether the infection has begun spreading from the lungs to other parts of the body.  
• Pulse oximetry is a test of blood-oxygen levels, something that may be called for in severe pneumonia. If levels are too low, the infection may be preventing your lungs from working properly.

In more advanced or severe cases—especially those involving people with compromised immunity—additional testing may be indicated, including:

• A sputum test, in which a sample of your phlegm is clinically evaluated, can determine the presence of a viral, bacterial, or fungal infection.
• Computerized tomography (CT) scan of the chest screens for damage to the lungs or other complications. This type of imaging relies on multiple X-rays to create a three-dimensional rendering of the affected area.
• Pleural fluid culture is necessary to assess if bacteria or fungi are spreading to the pleura, which is the tissue on the outside of the lungs and along the inside of the chest cavity. This requires testing samples from the fluid surrounding these tissues.
• Bronchoscopy involves using an endoscope—a camera at the end of a specialized, adjustable tube—to assess airways visually. With this device, healthcare providers can view video of the inside of your lungs.

Treatment

The treatment of pneumonia depends on the cause of the disease; what works for bacterial pneumonia, for instance, wouldn’t work for viral types. Following is a list of treatment approaches for each type of pneumonia:

• Bacterial pneumonia: The primary remedy for bacterial pneumonia is antibiotic medications. The specific choice of antibiotic and the duration of use are based on overall health status, other medications you’re taking, and the severity of your case. Using over-the-counter medications, taking comfort measures, and performing breathing exercises also help, with hospitalization necessary for severe cases.
• Viral pneumonia: The challenging aspect of viral pneumonia is that there are not many medications to eradicate it. If the influenza virus has caused pneumonia, antiviral medications, such as Tamiflu (oseltamivir) and Relenza (zanamivir), can help ease symptoms. Breathing treatments and over-the-counter medications help here, too.
• Fungal pneumonia: Antifungal drugs are the first-line treatment for fungal pneumonia, including those of the triazole class like Sporalax (itraconazole), Diflucan (fluconazole), and amphotericin.

Prognosis

Generally speaking, the success of recovery from pneumonia, with or without fever, depends on your health status. Most otherwise-healthy adults see relatively quick relief from symptoms with treatment. That said, if pneumonia is allowed to progress, or if you’re in a vulnerable or immunocompromised population, the disease can be deadly.

In rare cases, there are long-term effects, even after complete recovery. Children who’ve had pneumonia may develop lifelong breathing difficulties, for instance. Chronic effects can cause:

• Reduced capacity for exercise and fitness
• Worsening heart conditions
• Cognitive decline and decreased mental function
• Overall reduced quality-of-life

A Word From Verywell

Pneumonia without fever is particularly challenging because it presents as less severe than pneumonia that is accompanied by fever. However, every pneumonia case is different, and everyone suffers and recovers from it differently. Early detection and proper, timely treatment go a long way in ensuring better outcomes.

This is why it’s important to be mindful of how you’re feeling. If you suspect you have pneumonia and are having symptoms without fever, you should consult your healthcare provider. The sooner you reach out for treatment for pneumonia, the better off you’ll be.