Updated on: September 2, 2026 by John Ingham
Cotton fever is a term used to describe a sudden fever and systemic inflammatory response that can occur after intravenous drug use, historically in situations involving cotton filters.
Symptoms can begin rapidly and may include fever, severe chills, muscle aches, nausea, elevated heart rate, shortness of breath, and other symptoms that resemble a serious bloodstream infection.
The most important point is that someone experiencing these symptoms cannot safely assume they have cotton fever. Sepsis, infective endocarditis, bloodstream infections, pneumonia, and other potentially life-threatening complications associated with injection drug use can initially look similar.
Medical evaluation may therefore be necessary even when someone believes they have experienced cotton fever before.
Key Points
- Cotton fever describes a rapid inflammatory illness associated with injection drug use and contaminated injection practices.
- Its symptoms can closely resemble sepsis and serious bloodstream infections.
- Cotton fever is generally considered a diagnosis of exclusion; it should not be self-diagnosed when potentially life-threatening infection has not been ruled out.
- Brooks Healing Center provides treatment for opioid and other substance use disorders, including medical detox and medication-assisted treatment when clinically appropriate.
What is Cotton Fever?
Cotton fever is a condition that can happen to someone who has used cotton as a drug filter before injecting intravenous drugs. Its primary symptoms are an acute-onset fever and high white blood cell count. It causes a systemic inflammatory response within minutes of the intravenous (IV) drug use. Cotton fever is a well-recognized condition among people who inject drugs (PWID) but is less known among healthcare providers. Its overlap with serious infections makes medical evaluation important before the diagnosis is established.
What Causes Cotton Fever?
Intravenous drugs can be heated before being drawn into a syringe for injection. Once the drug is heated, it can be drawn through a cotton ball into the syringe as an inexpensive way to filter the drug.[1] Some users will even remove what has been filtered out in the cotton ball to use later, especially if their supply is running low. This is called “shooting the cottons”.
There are a few theories as to why cotton fever happens. One theory is that despite the cotton being there to filter out contaminates, it is not a medically sterile filter. Cotton contaminants can be drawn into the syringe and injected. Injecting the cotton contaminants can result in the sepsis-like symptoms of cotton fever.[2] A second theory is that some people have preformed antibodies to cotton while others do not. A third theory is that cotton fever may result from an endotoxin caused by bacteria such as Enterobacter agglomerans living in cotton plants.[3]
What Are The Symptoms of Cotton Fever?
Symptoms of cotton fever begin 15–30 minutes following injection and normally last six to twelve hours, but they can extend for 24-48 hours.[4] Symptoms attributed to cotton fever often resolve relatively quickly with supportive care, but antibiotics are not a specific treatment for a sterile inflammatory reaction. Clinicians may initially administer antibiotics when bacterial infection or sepsis cannot safely be excluded.
Common cotton fever symptoms include :[5]
- Fever (peaks at 101.3–104.5 °F)
- Extreme chills & uncontrollable shivering
- Gastrointestinal symptoms, including abdominal pain, nausea and vomiting
- Headache
- Muscle pains
- Back and kidney pain (can be dull, sharp, piercing, or burning)
- Excessive sweating
- General weakness and malaise
- Shortness of breath
- Tachycardia
- Chest pain
Less common cotton fever symptoms include: [6]
- Leg pain
- Joint pain
- Heart palpitations
- Dysphoria
- Fear of death
How Is Cotton Fever Treated?
There is no specific medication that “cures” cotton fever.
When someone who injects drugs develops fever, chills, rapid heart rate, or other systemic symptoms, the immediate challenge is determining whether the person has a self-limited inflammatory reaction or a potentially life-threatening infection.
Medical evaluation may include vital-sign monitoring, blood testing, blood cultures, imaging, or other testing depending on the symptoms and clinical situation.
Supportive care may include fluids and treatment for fever or discomfort. Antibiotics may be started when clinicians cannot initially rule out a bacterial infection, but antibiotics are not automatically required once a noninfectious cause has been established.
Because cotton fever can closely resemble sepsis, infective endocarditis, and other serious complications of injection drug use, healthcare professionals may need to perform diagnostic testing before concluding that symptoms are caused by cotton fever.
Recognizing the syndrome can help clinicians consider it as part of the differential diagnosis, but it should not be used as a reason to prematurely rule out potentially life-threatening infection.
Complications from Cotton Fever
Most complications people experience are a result of infection from their injection drug use. Infections can include:[9]
- Sepsis: an infection that has caused a full body response to the infection, resulting in organ failure, tissue damage, and death.
- Infective endocarditis: a bacterial infection that enters the bloodstream and settles in the heart lining, a heart valve, or blood vessels.
- Spinal epidural abscess: a central nervous system infection with a collection of pus and infectious materials causing an abscess along the spine.
- Other infections: People who inject drugs are susceptible to multiple different infections, including HIV/AIDS, hepatitis, and other bacterial and fungal infections.
Cotton fever and bacterial infection should be distinguished from one another. A sterile inflammatory reaction may resolve without infection, while nonsterile injection practices can separately introduce bacteria into the bloodstream and lead to bacteremia, sepsis, abscesses, or infective endocarditis.
Because the symptoms can overlap, medical evaluation is important when a person who injects drugs develops significant fever or systemic illness.
When to Seek Emergency Care
Someone who injects drugs should seek urgent medical evaluation for severe or persistent fever, difficulty breathing, chest pain, confusion, fainting, severe weakness, low blood pressure, a rapidly worsening condition, or other signs of serious illness.
A previous episode labeled “cotton fever” does not guarantee that a later episode is the same condition.
Cotton Fever and Drug Addiction
If injection drug use is connected to opioid or another substance use disorder, addressing the underlying addiction can reduce the risk of repeated injection-related complications.
Brooks Healing Center provides medical detox, residential addiction treatment, medication-assisted treatment when clinically appropriate, partial hospitalization programming, dual-diagnosis care, and sober living.
FAQ
What drugs cause cotton fever?
Cotton fever is not caused by a particular drug but by using cotton to filter the IV drug before injection. The contamination by the cotton causes cotton fever. Cotton fever is associated the most with heroin use (60%).[10] Other drugs include pentazocine, methamphetamines, cocaine, and other opioids.
How can Cotton Fever be prevented?
People who abuse IV drugs and use cotton filters are twice as likely to develop cotton fever.[11] Educating people about avoiding cotton filters and not re-injecting IV drugs from reused filters can help prevent cotton fever. Harm reduction methods include providing PWID proper membrane filters to filter drugs safely and clean syringes so they are not reused, decreasing one’s risk for infection.
Syringe service programs allow PWIDs to receive sterile syringes and needles at no cost. Supervised consumption programs allow PWIDs to inject their drugs in a safe location with medical personnel in the building to provide medical treatment in case of emergency. Harm reduction programs help prevent numerous health conditions, improve community health, and prevent deaths from overdose and other drug use complications.
Is there a cure for cotton fever?
There is no specific medication that cures cotton fever. Supportive care may relieve symptoms, but fever or systemic illness after injection drug use requires medical evaluation to rule out sepsis, infective endocarditis, or another serious infection. Seek urgent medical care for severe or persistent fever, difficulty breathing, chest pain, confusion, fainting, or rapidly worsening symptoms. Do not assume a previous episode means the current illness is cotton fever.
Why do doctors give antibiotics for cotton fever?
Clinicians may start antibiotics when bacterial infection or sepsis cannot safely be excluded. Cotton fever can resemble these life-threatening conditions, so diagnostic testing may be necessary. Antibiotics are not a specific treatment for a sterile inflammatory reaction and are not automatically required once a noninfectious cause has been established.
Sources:
[1] Zerr, A. M., Ku, K., & Kara, A. (2016). Cotton fever: a condition self-diagnosed by IV drug users. The Journal of the American Board of Family Medicine, 29(2), 276-279. Retrieved from https://www.jabfm.org/content/29/2/276 on 2024, Sept 4.
[2,5,6,7,8,10,11] Geedipally, H., Karki, S., Shirke, S., & Bhimani, R. (2022). Just a Bad Case of Cotton Fever: A Case Report and Literature Review. Cureus, 14(8). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9506875/ on 2024, Sept 4.
[3] Francis, M. J., Chin, J., Lomiguen, C. M., & Glaser, A. (2020). Cotton fever resulting in Enterobacter asburiae endocarditis. IDCases, 19, e00688. Retrieved from https://www.sciencedirect.com/science/article/pii/S2214250919303270?via%3Dihub on 2024, Sept 4.
[4] Xie, Y., Pope, B. A., & Hunter, A. J. (2016). Cotton Fever: Does the Patient Know Best? Journal of General Internal Medicine, 31(4), 442-444. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4803705/ on 2024, Sept 4.
[9] Tobarran, N., Huchison, J., Kershner, E., Chambers, A., Cumpston, K. L., & Wills, B. K. (2023). Cotton fever: A case report and review of the literature. JEM Reports, 2(2), 100030. Retrieved from https://www.sciencedirect.com/science/article/pii/S2773232023000263?via%3Dihub on 2024, Sept 4.
