A fever is a temporary elevation in body temperature, generally considered a reading of 100.4°F (38°C) or higher when measured orally or rectally. This rise in temperature is not an illness itself but rather a sign that the immune system is actively fighting off a perceived threat, typically a viral or bacterial infection. Determining when a fever requires a doctor’s visit depends significantly on the age of the patient and the presence of any accompanying symptoms.
When to Seek Care for Infants and Toddlers
Guidelines for the youngest patients are the most urgent and absolute because their immune systems are underdeveloped, and a fever can rapidly signal a serious infection. For any infant under three months of age, a rectal temperature of 100.4°F (38°C) or higher requires immediate medical attention. This single temperature reading is considered a potential emergency, and parents should proceed to the nearest emergency department without delay.
For children between three months and three years old, a temperature of 102.2°F (39°C) or higher should prompt a call to the pediatrician. A fever of 100.4°F or higher that persists for more than 24 hours in a child between 6 and 24 months also warrants a medical evaluation. If the child is excessively irritable, difficult to wake, or refuses to drink fluids, medical consultation is necessary regardless of the exact temperature reading.
Duration Thresholds for Older Children and Adults
For older children (roughly four years and up) and healthy adults, the duration of the fever becomes the primary factor in deciding when to seek non-emergency care. A single, high temperature spike that quickly resolves is usually less concerning than a persistent low-grade fever. Adults should contact a healthcare provider if a fever of 100.4°F or higher lasts longer than three to five days.
Older children should be seen by a doctor if a fever persists for more than 72 hours (three days). This prolonged timeline suggests the body may be struggling to overcome the infection. Medical attention is also necessary if a high fever initially broke but then returned after a brief period of normal temperature.
Critical Symptoms Requiring Emergency Care
Certain symptoms accompanying a fever mandate an immediate trip to the emergency room, regardless of the patient’s age or the temperature reading. These “red flag” signs indicate a potential complication or a severe underlying condition that requires rapid diagnosis and treatment. Seek emergency care immediately if the patient experiences:
- A stiff neck, severe headache, or sensitivity to light (suggesting meningitis).
- Difficulty breathing, severe chest pain, or any seizure activity.
- A rapidly spreading or non-blanching rash.
- Significant change in mental status, such as confusion, extreme drowsiness, or difficulty waking up.
- Inability to hold down fluids due to persistent vomiting or signs of severe dehydration.
Managing Fever at Home While Monitoring
While monitoring a fever at home, the focus should be on supportive care to maintain comfort and prevent complications like dehydration. Hydration is paramount, as a fever can cause the body to lose fluids more quickly through sweating. Drinking plenty of water, clear broth, or electrolyte-containing beverages helps to replenish lost fluids and minerals.
Rest is also an important component of recovery, conserving the energy the body needs to fight the infection. Over-the-counter fever-reducing medications, such as acetaminophen or ibuprofen, can be used to alleviate discomfort and lower the temperature, following the dosage instructions carefully. Aspirin should never be given to children or teenagers.