Hormones, friction, stress—it’s all connected.

Some spots appear without warning. On the neck, arms, or face, they can be puzzling. But a new scientific study offers some answers. It breaks down the most common causes and highlights factors that are often overlooked. Understanding these mechanisms can help you prevent them from appearing.

These marks on your skin aren’t random. Recent research sheds light on the processes behind the development of certain pigment spots. Their location isn’t always caused by sun exposure, nor is it only about aging. Your body is sending signals. You just need to learn how to read them.

Researchers followed a group of volunteers for several months. The goal: to understand why spots show up more often in some areas than others. The results show multiple overlapping factors—from lifestyle and genetics to exposure to irritants.

The Skin Reacts to What It Endures

Each part of your body faces different conditions. The face, hands, and neck are constantly exposed to daylight—even in winter. In response, the skin produces more melanin as protection. This natural defense can leave behind brown or pinkish marks.

But sunlight isn’t the whole story. The study also points to the role of repeated friction. Watches, bracelets, tight clothing—constant rubbing can sometimes trigger localized hyperpigmentation. The body reacts to the irritation by toughening the area, and in some cases, by darkening the skin.