Flu Emergency Warning Signs: When to Go to the ER

Emergency Signs in Adults

Seek emergency care immediately if you experience:[1][2]

• Difficulty breathing or shortness of breath — Feeling like you can't get enough air, even at rest[1]
• Persistent pain or pressure in the chest or abdomen — Not muscle soreness, but a squeezing or heavy sensation[1][3]
• Persistent dizziness, confusion, or inability to stay awake — Mental status changes are a red flag[1]
• Seizures[2]
• Not urinating — Sign of severe dehydration[3]
• Severe muscle pain — Beyond typical flu aches, especially if localized and intense[4]
• Severe weakness or unsteadiness — Trouble standing or walking[1]
• Fever or cough that improves, then returns or worsens — May indicate secondary bacterial pneumonia[1][5]
• Bluish lips or face — Sign of low oxygen levels (cyanosis)[1]

Emergency Signs in Children

Children can deteriorate quickly. Seek emergency care for:[1][2]

• Fast breathing or trouble breathing — Ribs pulling in with each breath, nostrils flaring[1]
• Bluish lips or face[1]
• Chest pain — Especially if the child can describe it[3]
• Severe muscle pain — Child refuses to walk or move[4]
• Dehydration — No urine for 8+ hours, dry mouth, crying without tears[2]
• Not alert or interacting when awake — Unusually drowsy, unresponsive[1]
• Seizures[2]
• Fever above 104°F (40°C) — Especially if not controlled by medication[3]
• Fever in infants under 12 weeks — Any fever in a very young infant requires immediate evaluation[1][5]
• Worsening of chronic medical conditions[1]

High-Risk Groups: Lower Threshold for Seeking Care

If you or someone you're caring for falls into any of these groups, contact a doctor early — don't wait for emergency signs:[1][2]

• Children under 5 (especially under 2)
• Adults 65 and older
• Pregnant women (and up to 2 weeks postpartum)
• People with chronic conditions: asthma, heart disease, diabetes, kidney disease, liver disease
• Immunocompromised individuals (cancer treatment, HIV/AIDS, organ transplant, long-term steroids)
• People with BMI ≥ 40
• Residents of nursing homes and long-term care facilities

Symptoms That Require Medical Attention (But Not ER)

Why Acting Quickly Matters

Flu complications can develop rapidly — sometimes within 24-48 hours of symptoms appearing. The most common serious complications include:[1][2]

• Pneumonia: Bacterial or viral. The leading cause of flu-related hospitalization[1]
• Sepsis: A life-threatening response to infection[4]
• Myocarditis: Inflammation of the heart muscle[5]
• Encephalitis: Inflammation of the brain[2]
• Multi-organ failure: In severe cases[4]
• Worsening of chronic conditions: Asthma attacks, heart failure exacerbation[1]