Nail cap deflation may be related to nail trauma, or it may be caused by micronutrient or vitamin deficiencies, gray nails and other reasons. 1. Nail trauma: If the nail cap is deformed by accidental collision or extrusion, it may cause the nail cap to be deflated, and may also be accompanied by symptoms such as nail bleeding and pain. 2. Trace element or vitamin deficiency: If the body lacks vitamin A, D or trace elements such as calcium and zinc due to excessive partiality or picky eating for a long period of time, it may lead to deflated fingernails, and in serious cases, the fingernails may also fall off easily. 3. Gray nails: clinically also known as onychomycosis, usually caused by fungal infections, if not timely and effective treatment, by the long-term stimulation of fungi, may cause nail cover deflation, may also be accompanied by thickening of the nails, nail color changes and other manifestations. There may be other reasons for deflated nails, so it is recommended to consult a doctor as soon as possible to identify the cause and then give targeted treatment.