What causes a bruised nail bed?

A bruised nail bed is primarily caused by a small injury to the area beneath the nail. This injury can occur from various minor traumas, such as hitting the nail against a hard surface or applying excessive pressure during activities. When the blood vessels underneath the nail are damaged due to this injury, blood can pool in the space between the nail plate and the nail bed, leading to the characteristic discoloration associated with bruising.

While a bad manicure may cause damage, it typically doesn't result in the symptom described as a bruised nail bed unless it is associated with trauma. Infections usually manifest with redness, swelling, or pus and do not typically cause bruising. Similarly, genetic disorders could affect the nails' appearance or structure but would not directly lead to a bruising effect as defined here. Understanding the relationship between minor trauma and the resulting bruising helps reinforce the importance of handling nails carefully during both personal care and professional nail treatments.