Dents can occur in fingernails due to underlying medical conditions, such as psoriasis, Reiter syndrome, incontinentia pigmenti and alopecia areata, according to EmpowHER. Fingernail dents can also be caused by vitamin deficiencies and thyroid imbalances.
Fingernail dents may appear in connection with a fungal infection. Some people develop deep ridges across the nails called Beau's lines, which may resemble dents. These form when a person falls ill or experiences some type of injury that interrupts their normal pattern of nail growth.
Beau's lines usually grow out on their own and do not require treatment, but these lines can indicate serious health conditions such as diabetes and peripheral vascular disease, according to Mayo Clinic. Similar to other nail abnormalities, Beau's lines can also signal a mineral deficiency. Beau's lines usually appear in all fingernails, but if the condition affects only a single nail, it may be a sign that a cyst or wart exists at the base of the nail causing pressure.
It is important for those with unexplained fingernail conditions to visit a doctor or dermatologist a proper diagnosis. Treatments vary according to a doctor's analysis.