What causes a depression on the forehead upon waking up in the morning?

Indentation on the forehead upon waking up in the morning may be caused by localized pressure, head trauma, or underlying kidney disease.

1. Localized Pressure

If sleeping posture is improper—for example, lying face down for prolonged periods—the fat, muscles, or subcutaneous tissues of the forehead may become compressed over time, leading to a slight indentation upon waking. This is a normal physiological phenomenon and generally requires no treatment as long as no other complications arise.

2. Head Trauma

If the forehead suffered physical impact the previous day and the injury was not taken seriously enough, an indentation might be noticed the next morning upon waking. In such cases, symptoms such as headache and nausea are often present as well. It is advisable to seek medical attention promptly and undergo a head CT scan for accurate diagnosis.

3. Kidney Disease

In patients with kidney disease, excessive fluid intake during the night may lead to edema in the soft tissues of the forehead. If pressure is applied to the head while sleeping, this may also result in the aforementioned symptoms.