Fever of 39°C, forehead not hot but body feels hot

Generally speaking, fever refers to an elevated body temperature. When the body temperature reaches 39°C, the forehead may not feel hot while the rest of the body does, which could be related to factors such as rapid heat dissipation from the forehead, relatively low ambient temperature, measurement errors, early signs of heatstroke, or autonomic nervous system dysfunction. Specific explanations are as follows:

1. Rapid heat dissipation from the forehead

Under normal circumstances, during a fever, blood circulation in the body accelerates. Since there are numerous blood vessels located in the forehead area, increased sweating occurs under conditions of faster blood flow, leading to a situation where the forehead feels cool while the body feels hot. This is a normal phenomenon and usually requires no intervention.

2. Relatively low environmental temperature

When a patient has a fever reaching 39°C, blood circulation increases accordingly. If the surrounding environment is relatively cold, the forehead exposed to air can experience physical cooling, whereas the rest of the body remains covered by clothing or blankets, limiting heat dissipation. This easily results in a cooler forehead but a hotter body. This is also a normal occurrence and generally does not require special treatment.

3. Measurement error

This may be caused by a faulty thermometer or incorrect measurement technique. It is recommended that patients take multiple temperature readings at different body sites to confirm results.

4. Early signs of heatstroke

This condition typically arises due to rising ambient temperatures, increased internal heat production, or impaired heat dissipation. Patients often experience symptoms such as dizziness, thirst, and excessive sweating after prolonged exposure to high temperatures. Body temperature may remain normal or slightly elevated, and the aforementioned discrepancy between forehead and body warmth may occur. Patients may follow medical advice to use medications such as Huoxiang Zhengqi Water or Shidi Shui for treatment.

5. Autonomic nervous system dysfunction

A small number of patients may not only perceive body heat with a cool forehead, but also experience dizziness, palpitations, and chest tightness. In such cases, the cause is likely autonomic nervous system dysfunction. Patients may take medications such as doxepin hydrochloride tablets or amitriptyline hydrochloride tablets as directed by a physician.

In addition, other factors such as excessive sweating on the forehead, external influences, or hyperthyroidism may also lead to a cool forehead with a hot body. If discomfort persists, patients are advised to seek timely medical evaluation to avoid delays in diagnosis and treatment.