High blood pressure does not directly cause fever. While these conditions can co-occur, high blood pressure is not the underlying reason for an elevated body temperature. Certain medical conditions, however, can lead to both appearing simultaneously.
Understanding Fever
Fever is an elevation in the body’s core temperature above its typical range, typically 100.4°F (38°C) or higher when measured orally. This physiological response often indicates the immune system is fighting an underlying issue.
Common causes of fever include infections from bacteria, viruses, or other microbes. Inflammatory processes, certain autoimmune conditions, and reactions to some medications can also trigger a fever. The body’s “thermostat” in the hypothalamus resets to a higher temperature, prompting processes to generate and conserve heat.
Understanding High Blood Pressure
High blood pressure, or hypertension, is a condition where the force of blood against artery walls is consistently too high. Sustained pressure can damage blood vessels and lead to serious health complications.
High blood pressure has two main types. Primary hypertension, the most common, typically develops gradually over many years with no single cause, often influenced by lifestyle and genetics. Secondary hypertension, conversely, has a specific underlying cause like kidney disease, certain medications, or other medical conditions.
Conditions Presenting with Both
While high blood pressure does not directly cause fever, several underlying medical conditions can cause both. These conditions indicate a systemic issue affecting various bodily functions.
Systemic infections are a common cause for both symptoms. Severe bacterial infections, such as pyelonephritis or sepsis, can trigger a strong inflammatory response. The body’s stress response to widespread infection can temporarily increase blood pressure.
Inflammatory or autoimmune conditions can also cause both fever and elevated blood pressure. Flare-ups of conditions like lupus or vasculitis involve systemic inflammation causing fever. This inflammation may also affect blood vessels or kidney function, potentially elevating blood pressure.
Certain drug reactions can also be a link. Some medications can induce fever as a side effect, and sometimes influence blood pressure. It is important to review all medications if these symptoms appear together.
Pheochromocytoma, a rare adrenal gland tumor, can cause both symptoms. This tumor releases excess hormones like adrenaline and noradrenaline, causing sudden, severe blood pressure spikes. These hormonal surges can also cause sweating, flushing, and sometimes fever due to increased metabolic rate.
When to Seek Medical Attention
Seek medical attention for persistent, unusually high fever, or other concerning symptoms. A temperature above 103°F (39.4°C) warrants medical evaluation.
Consult a healthcare professional if fever accompanies severe headache, confusion, difficulty breathing, chest pain, or a sudden, significant elevation in blood pressure. These combined symptoms could indicate a serious underlying condition requiring prompt diagnosis and treatment.