What Is Acute Illness?
An acute illness is a health problem that starts suddenly, with symptoms that appear, change or worsen quickly. "Acute" means sudden, and it is the opposite of chronic. Common examples include colds, flu, sore throats, earaches and bladder infections.
Acute does not always mean minor. Acute conditions range from a broken bone to an asthma attack. Many are short-lived: most people with flu recover in a few days to less than two weeks.
Acute Illness at a Glance
| Also called | Acute condition |
|---|---|
| Common causes | Viruses, bacteria and injuries |
| Who gets it | Anyone. Older adults, young children and people with certain health conditions face a higher risk of severe respiratory illness. |
| Is it serious? | Ranges from mild to severe; some need emergency care |
| Diagnosis | Depends on the cause; sometimes a quick test such as a rapid strep test or urinalysis |
| Treatment | Symptom relief, antibiotics for bacterial infections or antivirals for flu and COVID-19 |
| Contagious? | Many acute infections are, including flu, strep throat and norovirus |
What Are the Symptoms of Acute Illness?
The symptoms of an acute illness depend on its cause:
- Respiratory infections (colds, flu, COVID-19, RSV): runny or stuffy nose, sore throat, cough, fever, chills, body aches and fatigue. Flu starts abruptly. A cold starts gradually.
- Strep throat: a sore throat that starts very quickly, pain when swallowing and fever
- Acute bronchitis ("chest cold"): a cough that can last three weeks or more
- Stomach bug (norovirus): diarrhea, vomiting, nausea and stomach pain, starting 12 to 48 hours after exposure
- Bladder infection (acute cystitis): pain or burning with urination, a strong need to urinate often and cloudy or bloody urine
What Causes Acute Illness?
Many common acute illnesses are infections caused by viruses or bacteria. Others result from injuries, such as sprains or minor broken bones. Viruses cause most sore throats, and acute bronchitis is almost always viral. Bladder infections are most often caused by bacteria.
The risk of getting very sick from a respiratory illness is higher for adults 65 and older, children younger than 2, pregnant people, and people with chronic lung disease, heart disease, diabetes, chronic kidney disease or a weakened immune system.
Complications and Outlook
Many acute illnesses clear up with time or short treatment, but some cause complications:
- Flu can cause ear infections, pneumonia and sepsis, and can worsen asthma or heart disease.
- Strep throat can lead to abscesses, rheumatic fever or a kidney disease.
- Vomiting and diarrhea can cause dehydration, especially in young children and older adults.
Some acute conditions, such as a first asthma attack, may lead to a chronic condition if untreated.
How Is Acute Illness Diagnosed?
How acute illness is diagnosed depends on its cause, and a quick test can sometimes confirm it. A rapid test can check a sore throat for strep, and rapid tests can detect respiratory viruses. A urinalysis can usually diagnose a bladder infection.
How Is Acute Illness Treated?
Treatment for acute illness depends on its cause: many viral illnesses need only symptom care, while bacterial infections may need antibiotics.
Symptom Relief
- Rest and drink plenty of fluids.
- Honey can ease a cough in anyone at least 1 year old.
- Ask about over-the-counter pain relievers and fever reducers. Over-the-counter cough and cold medicines are not recommended for children younger than 6.
Antibiotics and Antivirals
Antibiotics don't work against viruses, and unneeded antibiotics can cause side effects such as rash, severe allergic reactions and C. diff diarrhea. In advice for adults, the American College of Physicians (ACP) and CDC advise no antibiotics for the common cold and antibiotics for a sore throat only if strep is confirmed. Strep throat and bladder infections are treated with antibiotics.
For flu or COVID-19, antivirals can lessen symptoms and shorten illness. Flu treatment should start within 2 days of symptoms, and COVID-19 treatment within 5 to 7 days.
Can You Prevent Acute Illness?
You can't prevent every acute illness, but simple habits lower your risk of common infections:
- Stay up to date on vaccines for flu, COVID-19 and RSV (for eligible groups).
- Wash your hands with soap for at least 20 seconds, or, if soap and water aren't available, use hand sanitizer with at least 60% alcohol.
- Cover coughs and sneezes, and don't share cups or utensils with sick people.
- With a respiratory virus, stay home until symptoms are improving and you've been fever-free for at least 24 hours without fever-reducing medicine.
When Should You See a Clinician About Acute Illness?
See a clinician about an acute illness if symptoms are severe, last longer than expected or get better and then worse. For cold-like symptoms, CDC advises seeking care for:
- Trouble breathing or fast breathing
- Dehydration
- A fever lasting longer than 4 days
- Symptoms lasting more than 10 days without improving
- Symptoms that improve, then return or worsen
Call 911 for severe chest pain or pressure, severe shortness of breath, sudden weakness on one side of the body or a seizure.
Acute Illness vs. Chronic Illness
| Acute illness | Chronic illness | |
|---|---|---|
| Onset | Sudden | Develops over a long time |
| How long it lasts | Often days to weeks | 1 year or more |
| Examples | Flu, strep throat, a broken bone | Asthma, osteoporosis, heart disease, diabetes |
| Care needed | From home care to emergency care | Ongoing medical attention, limits on daily activities, or both |
The two can overlap. Osteoporosis, a chronic condition, can cause a broken bone, an acute one.
Acute Illness Care at GENEVA
At GENEVA Primary Care & Med Spa in Alpharetta, GA, a provider evaluates your symptoms and health history, then recommends treatment at GENEVA or a referral to a specialist.
You can raise a new illness during a primary care visit or learn about telemedicine visits. GENEVA serves patients from Alpharetta, Johns Creek, Milton, Roswell and Cumming.
Related Terms
- Pediatric Acute Care
- Urinary Tract Infection (UTI)
- Dehydration
- Vaccination
- Chronic Disease Management
- Telemedicine
Acute Illness FAQs
Is an acute illness serious?
Many acute illnesses are mild and get better on their own or with short treatment, but some can become serious. Flu, for example, can lead to pneumonia, sepsis or a worsening of heart disease. Adults 65 and older, children under 2, pregnant people and people with chronic lung disease, heart disease, diabetes or a weakened immune system are more likely to get very sick from respiratory illnesses. Call 911 for severe chest pain, severe shortness of breath or sudden weakness on one side of the body.
How long does an acute illness last?
Many acute illnesses last days to a few weeks, depending on the cause. Most people with flu recover in a few days to less than two weeks, and most people with norovirus get better within 1 to 3 days. A cough from acute bronchitis can last three weeks or more. CDC advises seeing a clinician if symptoms last more than 10 days without improving, a fever lasts longer than 4 days, or symptoms improve and then return or worsen.
Do you need antibiotics for an acute illness?
Antibiotics help only acute illnesses caused by bacteria, such as strep throat or a bladder infection, because antibiotics don't work against viruses. Colds and flu are caused by viruses. In advice for adults, the American College of Physicians and CDC advise against antibiotics for the common cold and recommend them for a sore throat only when strep is confirmed. Unneeded antibiotics can cause rash, severe allergic reactions and C. diff diarrhea. For flu or COVID-19, ask about antivirals: flu treatment should start within 2 days of symptoms, COVID-19 treatment within 5 to 7 days.
What is the difference between acute and chronic illness?
An acute illness starts suddenly, while a chronic illness develops over time and lasts 1 year or more. CDC defines chronic diseases as conditions that last at least a year and need ongoing medical attention, limit daily activities, or both. Asthma and diabetes are chronic; flu is acute. The two can overlap: an asthma attack is an acute event within chronic asthma, and some untreated acute conditions may lead to a chronic one.
Should you go to urgent care or the ER for an acute illness?
Go to the emergency room or call 911 if an acute illness could be life threatening, and use your provider's office or urgent care for milder problems. Emergency signs include trouble breathing, severe chest pain, sudden confusion, heavy bleeding, or a high fever with a headache and stiff neck. If the problem isn't life threatening and you can't see your provider soon enough, urgent care can handle colds, flu, earaches, sore throats and minor injuries. MedlinePlus notes that emergency care can cost 2 to 3 times or more than the same care in a provider's office.
Can a primary care provider treat acute illness?
Yes. A primary care provider can evaluate common acute illnesses such as colds, flu, sore throats, earaches and bladder infections. Some can be confirmed with a quick test, such as a rapid strep test for a sore throat or a urinalysis for a bladder infection. At GENEVA in Alpharetta, your provider evaluates your symptoms and then recommends treatment at GENEVA or a referral to a specialist. If you can't see your provider soon enough and the problem isn't life threatening, urgent care is an option.