Vertical lines on the thumbnail are generally caused by malnutrition of the nail, nail fungal infection, other skin diseases, internal medical diseases, etc. If the nail is injured, or if there is a habit of partial eating, leading to a lack of corresponding trace elements in the body, it may lead to malnutrition of the nail, which may in turn cause vertical lines on the nail. In addition, the nail is prone to vertical lines when infected with fungi, which is also relatively common in clinical practice.
The vertical lines on the thumbnail may be caused by the following common reasons: 1. Malnutrition of the nail. The causes of nail malnutrition are complex, often related to local trauma or lack of trace elements caused by partial eating. In addition, some chronic chemical stimuli can also cause nail malnutrition, such as excessive use of detergents, disinfectants, or chemical corrosion from some nail beauty products. 2. Nail fungal infection. Nail fungal infection is usually caused by fungal infection of the nail plate, and vertical lines are a very common symptom of nail fungal infection. 3. Other skin diseases can cause changes in nails, such as psoriasis and lichen planus. These skin diseases often accompany changes in nails, and vertical lines on nails are a common accompanying change. 4. It is related to internal medical diseases, manifesting as vertical lines on nails. For example, some endocrine diseases may also cause vertical lines on nails in these patients.