Is a temperature of 100.4 degrees Fahrenheit (F) considered hyperthermia or fever?

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Last updated: May 1, 2025 • View editorial policy

From the Guidelines

Yes, 100.4°F (38°C) is considered a fever in adults and children. A normal body temperature typically ranges from 97°F to 99°F (36.1°C to 37.2°C), with 98.6°F (37°C) being the average. For most adults and children, a temperature of 100.4°F or higher indicates a fever, which is the body's natural response to infection or inflammation 1.

Definition of Fever

The definition of fever can vary depending on the context and population. However, a commonly used definition is a rectal temperature of greater than or equal to 38.0°C (100.4°F), documented in the clinical setting or at home within the past 24 hours 1.

Management of Fever

If you have a fever, you can manage mild cases at home with rest, fluids, and over-the-counter medications like acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) following package dosing instructions. However, seek medical attention if your fever exceeds 103°F (39.4°C), lasts more than three days, or is accompanied by severe symptoms like difficulty breathing, chest pain, confusion, severe headache, stiff neck, persistent vomiting, or if you have underlying health conditions that make fever more concerning 2.

Special Considerations

For infants and young children, doctors may use slightly different thresholds to define fever. It's essential to consult with a healthcare professional for personalized advice on managing fever in these populations 1.

Key Points

  • 100.4°F (38°C) is considered a fever in adults and children
  • Fever is the body's natural response to infection or inflammation
  • Manage mild cases at home with rest, fluids, and over-the-counter medications
  • Seek medical attention if fever exceeds 103°F (39.4°C), lasts more than three days, or is accompanied by severe symptoms.

From the Research

Definition of Fever

  • Fever is generally defined as a body temperature above 98.6°F (37°C) 3, 4, 5, 6, 7
  • However, the exact temperature that constitutes a fever can vary depending on the source and the individual's normal body temperature

Temperature of 100.4°F

  • A temperature of 100.4°F is generally considered to be a low-grade fever 3, 4, 5, 6, 7
  • This temperature is slightly above the normal body temperature range, but it is not typically considered to be a high fever

Treatment of Fever

  • The treatment of fever typically involves the use of antipyretic medications such as acetaminophen or ibuprofen 3, 4, 5, 6, 7
  • The choice of medication and the dosage will depend on the individual's age, weight, and medical history, as well as the severity of the fever

Studies on Fever Treatment

  • Several studies have compared the efficacy of different treatment regimens for fever, including monotherapy with acetaminophen or ibuprofen, and combination or alternating therapy with both medications 3, 4, 5, 6, 7
  • The results of these studies have been mixed, with some showing that combination or alternating therapy may be more effective than monotherapy, while others have found no significant difference between the different treatment regimens

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.