The causes of fine black lines inside the fingernail include bruises caused by trauma, fungal infection, or onychomycosis, subnail melanoma and so on.
1. Local bruising: when the finger is squeezed, smashed, collision and other external forces, bruising can occur under the nail, and during the recovery period, there are tiny black lines inside the fingernail, which are often irregular black lines with unclear boundaries. This situation with the dissipation of bruises will gradually disappear, do not need to worry.
2. Fungal infection: such as nail fungus patients, nail plate by fungal infection, nail surface can appear discoloration, thickening and other abnormal symptoms. If it is clear that the nail is infected by fungus, you need to follow the doctor’s instructions to use ketoconazole and other antifungal drugs for treatment.
3. Nail nevus tumor: nails grow out from the nail matrix, if there is a pigmented nevus in the nail matrix, it can produce pigment, and a thin black line will come out from the fingernail.
4. Subnail melanoma: longitudinal pigmented bands or diffuse subnail discoloration may appear inside the fingernail.
If there is a fine black line inside the fingernail, without a clear history of trauma to the fingernail or accompanied by other abnormal manifestations of the nail, it is recommended to consult a doctor for examination in a timely manner, so as to avoid delaying the condition after clarifying the cause of the disease.