Migraines are severe, often debilitating headaches that frequently include secondary neurological symptoms like heightened sensitivity to light and sound, and nausea. Fever, in contrast, is the body’s controlled elevation of its core temperature, typically in response to an infection or inflammation. The question of whether a migraine attack can cause this systemic temperature rise is common among those who experience intense thermal discomfort during an episode. The scientific consensus is that a true, clinical fever does not result from the neurological processes of a migraine.
Defining True Fever vs. Temperature Fluctuation
A true fever is defined by medical professionals as a measured body temperature of 100.4°F (38°C) or higher. This threshold is considered a clinically significant elevation of the body’s thermoregulatory set point. The body’s temperature naturally fluctuates throughout a 24-hour cycle due to circadian rhythms. These variations can range by as much as 0.9°F or 0.5°C. Feeling warm or experiencing minor shifts in temperature is not the same as having a fever, as a person can feel hot or cold without their core temperature crossing the 100.4°F mark.
The Direct Relationship: Why Migraines Do Not Cause Fever
Migraines are primarily a neurological event involving the activation of the trigeminovascular system. This activation releases specific neuropeptides, such as Calcitonin Gene-Related Peptide (CGRP), which contribute to pain signaling and neurogenic inflammation. This neurological process is distinct from the mechanism that causes fever. Fever results when immune cells release pyrogens that travel to the hypothalamus, the body’s thermostat, raising the thermal set point. Migraine pathology does not involve the systemic release of these pyrogens, meaning the headache lacks the immunological component required for a true fever.
Autonomic Changes and Thermal Sensations During Migraines
While migraines do not cause a fever, they frequently involve the autonomic nervous system (ANS), leading to thermal sensations that mimic one. The ANS controls involuntary functions, including heart rate, blood pressure, and temperature regulation. Migraine attacks can disrupt the balance between the sympathetic and parasympathetic branches of this system. A temporary ANS imbalance can manifest as flushing, sweating, or intense chills and shivering. These symptoms reflect changes in how the body manages heat at the periphery, such as altering blood flow near the skin, rather than an elevation of the core temperature set point.
Warning Signs: When Fever and Headache Signal an Emergency
The simultaneous occurrence of a true fever and a severe headache signals a need for immediate medical evaluation. This combination is characteristic of serious, non-migraine conditions requiring urgent intervention. Examples include meningitis (inflammation of the membranes surrounding the brain and spinal cord) and encephalitis (inflammation of the brain itself). Patients should seek emergency care if a severe headache is accompanied by a high fever and other specific red flags. These accompanying symptoms include a stiff neck, sudden mental status changes, confusion, or a non-blanching rash.