Dermatologists have studied skin cells under a microscope to understand how Grover’s disease happens. The outermost layer of skin is called the horny layer. People with Grover’s disease have an abnormal horny layer that disrupts how the skin cells attach to each other. When the skin cells detach (a process called lysis), bumps or blisters form.
Scientists don’t know for sure what causes this abnormality. Some doctors believe it’s caused by excessive environmental damage to the skin that’s occurred over many years. Other doctors believe excessive heat and sweating causes Grover’s disease. This is because some people first notice a breakout after using steam baths or hot tubs.
One recorded case of Grover’s disease has been linked back to, or at least co-occurred alongside, skin parasites.