[{"@context":"https:\/\/schema.org\/","@type":"Article","@id":"https:\/\/share-dev.upmc.com\/2026\/07\/dangerous-fever-warning-signs\/#Article","mainEntityOfPage":"https:\/\/share-dev.upmc.com\/2026\/07\/dangerous-fever-warning-signs\/","headline":"How to Tell if a Fever is Dangerous: Warning Signs and Treatment Tips","name":"How to Tell if a Fever is Dangerous: Warning Signs and Treatment Tips","description":"Everyone comes down with a fever now and then. But how can you tell if your high temperature is serious? Learn more about fevers and which symptoms make them dangerous. What Is a Fever? A fever is when your body temperature is higher than normal, which is 98.6 F (37.0 C) for most adults. If […]","datePublished":"2026-07-31","dateModified":"2026-07-31","author":{"@type":"Organization","@id":"https:\/\/www.upmc.com\/","name":"UPMC","url":"https:\/\/www.upmc.com\/","sameAs":"https:\/\/share-dev.upmc.com\/upmc\/","parentOrganization":"UPMC"},"publisher":{"@type":"Organization","name":"UPMC HealthBeat","logo":{"@type":"ImageObject","@id":"https:\/\/share-dev.upmc.com\/wp-content\/uploads\/2019\/04\/UPMC-HealthBeat-Logo.png","url":"https:\/\/share-dev.upmc.com\/wp-content\/uploads\/2019\/04\/UPMC-HealthBeat-Logo.png","width":600,"height":60}},"image":{"@type":"ImageObject","@id":"https:\/\/share-dev.upmc.com\/wp-content\/uploads\/2026\/07\/GettyImages-2151539372-e1785521097247.jpg","url":"https:\/\/share-dev.upmc.com\/wp-content\/uploads\/2026\/07\/GettyImages-2151539372-e1785521097247.jpg","height":866,"width":2000},"url":"https:\/\/share-dev.upmc.com\/2026\/07\/dangerous-fever-warning-signs\/","about":["Cold and Flu"],"wordCount":1383,"articleBody":"Everyone comes down with a fever now and then. But how can you tell if your high temperature is serious?Learn more about fevers and which symptoms make them dangerous.What Is a Fever?A fever is when your body temperature is higher than normal, which is 98.6 F (37.0 C) for most adults. If your body temperature rises to or above 100.4 F (38.0 C), you might have a fever.You should only see temporary changes in your temperature from day to day. But it\u2019s normal for it to rise a bit throughout the day.Your clothes, environment, mood, and medications can all bring your temperature up. If you menstruate, having your period can also make you feel warmer than usual.Common fever symptomsIf you have a fever, your symptoms may include:Chills.Dehydration.Headache or body aches.Lack of appetite.Nausea\/vomiting.Rash.Sweating.Weakness.High fevers can have serious symptoms that require medical attention. Call your doctor if you have a high fever and:Breathing problems.Cognitive issues or confusion.Convulsions\/seizures.Headache.Loss of consciousness.Severe pain, especially in the head, chest, or stomach.Pain while peeing.Rash or bruises.Stiff neck.Swelling.Urinary discharge.Why Do You Get a Fever?A fever isn\u2019t an infection, but it’s a symptom of one \u2014 and a tool for preventing more health complications. Sometimes, your body responds to new bacteria or viruses with a fever. The higher temperature level makes it harder for the infection to survive.When you get a fever, your body activates your immune system, which is responsible for fighting infection. You can get a fever as a symptom of many health issues, including:Appendicitis.Bladder, ear, skin, or sinus infections.Blood clots.Cancer.Colds and flus.Lupus.Respiratory illnesses, including bronchitis and pneumonia.Rheumatoid arthritis.How to Treat a Fever at HomeFevers are uncomfortable, so it\u2019s normal to want to treat them quickly. But most fevers go away on their own if you let them run their course.There are ways to lessen the side effects of an everyday fever:Draw a warm bath \u2014 Soaking in the tub can make you feel more relaxed and relieve some of the aches from your fever.Drink lots of water \u2014 Staying hydrated is one of the most important parts of recovering from a fever. Fluids prevent dehydration, a common fever side effect.Rest as often as possible \u2014 This is an important step in fighting infection. Even when you can\u2019t sleep, try to stay in bed and avoid overexerting yourself.Stay in a cool environment \u2014 Keeping your room cool can stop your temperature from spiking even further.Take over-the-counter (OTC) painkillers \u2014 Acetaminophen and ibuprofen can relieve pain and bring down your temperature. Make sure to check with a doctor if you plan on giving this type of medication to kids.Use a cool compress to bring down your temperature \u2014 Add cool water to a washcloth and apply it to your head or wrists to help lower your temperature.Wear comfortable, cool clothing \u2014 Breathable clothes help you avoid overheating. Try to resist the urge to layer up and opt for light, comfortable clothing instead.If these strategies don’t bring relief, your fever might be more serious. Reach out to your primary care provider (PCP) if a fever persists for more than seven days.What to avoid when you have a feverThere are many misconceptions surrounding treating fevers. Methods that seem ideal for recovery can have the opposite impact. For instance, if you have a fever:Avoid an ice bath \u2014 Extreme cold may seem logical when combating a high temperature, but ice baths are dangerous when you’re fighting an infection. Your temperature drops quickly in an ice bath, which can send your body into shock.Don\u2019t apply rubbing alcohol to your body \u2014 There’s a myth that rubbing alcohol brings down your temperature. This method runs the risk of causing serious issues if your skin absorbs the product.Don’t try to break it through sweating \u2014 Covering yourself in blankets and layers can make you warmer, bringing your temperature up even more. Try to manage chills and body aches with alternative methods.How Can You Prevent a Fever?Fevers are extremely common. But there are steps you can take to avoid infections that bring on fevers, such as:Dressing appropriately for your environment \u2014 When you exercise, wear lightweight clothing that keeps you cool.Not sharing personal items \u2014 Don’t use the same cups, products, or eating utensils as your friends and family. Even if someone you know isn\u2019t visibly sick, they could be carrying a fever-causing infection.Staying vaccinated \u2014 Common illnesses, including the flu, COVID-19, and shingles, all have vaccines that lessen your likelihood of contracting them.Washing your hands \u2014 Always clean your hands before you touch your face, use the restroom, or spend time with large groups of people. You should also wash your hands before and after you eat.When to See a Doctor for a FeverSometimes, a fever can suggest you\u2019re fighting a larger health issue, or your symptoms may not be normal.In rare cases, a fever can be a sign of a serious health complication. Know the warning signs of a fever that comes alongside a severe issue.How do you know if a high fever is dangerous?If your temperature rises above 103.0 F (39.4 C), you have a high-grade fever.In severe illnesses, this kind of high fever might be part of the infection. But if your high-grade fever lasts for more than 48 hours, you should seek medical attention to rule out something serious.Fevers that stick around longer than usual can be dangerous. In some cases, a high fever can cause brain damage or even death.Should you go to the emergency department for my fever?If your fever is a sign of a more pressing health issue, visit your nearest emergency department (ED). Also seek immediate care if you have the following issues with your fever:Bruising, rashes, and swelling.Confusion, brain fog, and cognitive issues.Fainting and losing consciousness.Pain when you urinate.Seizures.Severe pain in your head, chest, or stomach.Stiff neck.Trouble breathing.Take note of the symptoms you experience while you have a fever. Staying aware of your symptoms can keep you safe from further complications.Fever warning signs in babiesFever symptoms can look slightly different in babies. If you\u2019re a parent or take care of young children, learn the signs of a dangerous fever.Babies typically require attention for fevers sooner \u2014 immune systems are much weaker in infancy. If your baby is under 3 months old and has a fever of 100.4 F (38.0 C), call your doctor.Children older than 3 months and up to 3 years old require different treatment. Call your doctor if your child between these ages has a fever of 100.4 F (38.0 C) or higher.If your newborn child under the age of one month is presenting with a fever of 100.4 F (38.0 C) or higher, they should be evaluated immediately be a medical professional.Fevers can make children lethargic and fussy. If you notice your child acting out more than usual while they’re sick, you should check in with their pediatrician.Do Vaccines Cause Fevers?You might notice that after you get a vaccine, you feel a bit under the weather.Body aches and fevers are common vaccine side effects. These symptoms mean the vaccine is working as it should. Having this reaction doesn\u2019t necessarily mean you have an allergy to the vaccine.Usually, vaccine side effects don’t last long. Try using OTC medicine to treat a vaccine-related fever, and get extra rest, too. But if your fever doesn’t lessen after you treat it with medication, talk to your provider.Don\u2019t let side effects deter you from getting vaccinated. Vaccines are important in helping you stay healthy throughout the year.SourcesAmerican Academy of Pediatrics, Fever and Your Baby. Accessed May 2026. https:\/\/www.healthychildren.org\/English\/health-issues\/conditions\/fever\/Pages\/Fever-and-Your-Baby.aspx?_gl=1*qq882w*_ga*NjY1NjQzMTAxLjE3Nzk4MTgzMjU.*_ga_FD9D3XZVQQ*czE3Nzk4MjI1MjUkbzIkZzEkdDE3Nzk4MjI3NTkkajQ4JGwwJGgw. Link. U.S. Centers for Disease Control and Prevention, Febrile Seizures and Vaccines. Accessed May 2026. https:\/\/www.cdc.gov\/vaccine-safety\/about\/febrile-seizures.html. 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