Which symptoms should never be managed at home, and when do you need a doctor?

Call your emergency number now

Use 911 (US), 999 (UK) or 112 (EU); do not drive yourself^1,2. Do not wait for a remedy if you have:

• Stroke signs. A drooping face, weakness in one arm, slurred or confused speech. Also sudden numbness down one side, loss of sight, dizziness or a severe headache. Signs that fade still need urgent care¹.
• Heart attack or collapse. Tight, squeezing or spreading chest pain (arm, neck, jaw), severe difficulty breathing, nausea, sweating, pale or blue skin, or someone who has passed out and is not responding normally². In a registry of 1.1 million heart attacks, 42 percent of women and 31 percent of men had no chest pain³.
• Sepsis. With an infection: confusion or slurred speech, uncontrollable shivering, fast breathing, blue, pale or blotchy skin, a very high or low temperature, or no urine all day⁴.
• Meningitis. Fever with a stiff neck, a very painful headache, dislike of bright light, confusion, or a rash that does not fade under a pressed glass⁵.
• A baby under 3 months with a temperature of 38 °C (100.4 °F) or higher, or 39 °C (102.2 °F) at 3 to 6 months^4,5.
• Severe allergic reaction. Swollen lips, tongue or throat, trouble breathing or swallowing, faintness or confusion soon after a food, medicine or sting. Use an adrenaline auto-injector if you have one⁶.
• Sudden, severe headache that peaks within an hour, especially instantly, or with neck pain, fainting or onset during exertion⁸.
• Thoughts of suicide. If you are in immediate danger, call your emergency number. In the US you can also call, text or chat 988, free and confidential, around the clock⁹.

See a doctor soon

NICE's referral guideline for suspected cancer names these unexplained or persistent symptoms⁷:

• A change in bowel habit; rectal bleeding (blood in the stool) from age 50 on its own, or at any age with abdominal pain or weight loss.
• Unexplained weight loss, especially with abdominal pain from age 40, or on its own from age 50.
• Coughing up blood from age 40, or two or more of cough, fatigue, breathlessness, chest pain, weight loss or appetite loss from age 40 (one is enough if you have ever smoked).
• Difficulty swallowing, a new breast lump from age 30, a lump in the neck, a mouth ulcer lasting over 3 weeks, hoarseness from age 45, or visible blood in the urine.

A symptom on this list usually does not mean cancer: of 326,240 adults with unexpected weight loss, 4.8 percent were diagnosed with cancer within six months¹⁰. It does mean getting checked. For fevers, see fever: friend or foe?.

Why minutes matter

Emberson and colleagues pooled individual data from 6,756 patients in nine randomized trials of intravenous alteplase for ischaemic stroke. Treatment within 3.0 hours gave a good outcome (no significant disability at 3 to 6 months) in 32.9 percent versus 23.1 percent of controls (odds ratio 1.75, 95% CI 1.35 to 2.27). Between 3.0 and 4.5 hours it was 35.3 versus 30.1 percent (1.26, 1.05 to 1.51), and after 4.5 hours the gain was not significant (1.15, 0.95 to 1.40). Symptomatic bleeding in the brain rose from 1.3 to 6.8 percent, so the treatment needs a scan and a specialist, which is why stroke belongs in hospital, not at home¹¹. In sepsis, a New York study of 49,331 patients at 149 hospitals found that each hour of delay in completing the 3-hour care bundle was linked to higher risk-adjusted in-hospital mortality (odds ratio 1.04 per hour, 1.02 to 1.05), as was each hour of delay to antibiotics (1.04, 1.03 to 1.06); median time to antibiotics was 0.95 hours. It was observational, so it shows association, not proof¹².

Symptoms that do not look like the textbook

A US registry of 1,143,513 people hospitalized with a heart attack found that 42.0 percent of women and 30.7 percent of men had no chest pain at presentation. In-hospital mortality was 14.6 percent for women and 10.3 percent for men, and younger women without chest pain fared worse than younger men³. The NHS notes that a child or adult with sepsis or meningitis may not have every listed symptom^4,5.

Headache and cancer red flags

In 2,131 Canadian emergency patients whose headache peaked within an hour and who had a normal neurological exam, 132 (6.2 percent) had a subarachnoid hemorrhage, bleeding around the brain. A rule using age 40 or older, neck pain or stiffness, witnessed loss of consciousness or onset during exertion caught 98.5 percent of them (95% CI 94.6 to 99.6) with 27.5 percent specificity. Adding thunderclap onset and limited neck flexion gave the Ottawa SAH Rule, with 100 percent sensitivity (97.2 to 100) and 15.3 percent specificity. It applies only to this group and needs more implementation research⁸.

For cancer, Nicholson and colleagues followed 326,240 adults in English primary care records with a code for unexpected weight loss. Of them, 15,624 (4.8 percent) were diagnosed with cancer within six months, 96.3 percent aged 50 or older. The positive predictive value passed NICE's 3 percent threshold for urgent investigation in men 50 and over and women 60 and over; in younger adults it was below 3 percent unless other features were present, and no normal blood test ruled cancer out¹⁰. NICE ties urgent testing to symptom-and-age combinations, such as an urgent chest X-ray from age 40 for two or more unexplained respiratory or general symptoms, and a stool test from age 50 for unexplained rectal bleeding, abdominal pain or weight loss⁷.

How good are red flags?

Red-flag lists are screening aids, not diagnoses. The headache rule is built to miss almost no bleeds, so most people it flags are fine⁸. Most people with unexpected weight loss do not have cancer within six months (95.2 percent in the study above), but the minority who do are why thresholds are set by age and added features¹⁰. That study is an update of an earlier BMJ paper that was retracted, so its exact figures deserve caution¹⁰. The emergency lists come from UK public-health pages, and emergency numbers and care pathways differ by country^1,2,4,5,6. Use the lists as a floor for acting, and use a clinician or a nurse advice line for gray areas.

Bottom line

Confidence is fairly high (4 of 5). Government and guideline sources agree on the emergency signs^1,2,4,5,6, studies show delay worsens stroke and sepsis outcomes^11,12, and heart attacks often lack chest pain, especially in women³. Individual red flags are imperfect, which is why they are built to err toward checking^8,10. Natural remedies are fine for minor problems, but never as a substitute for care when these signs appear.