What causes a hole to form at the base of the fingernail?

Generally speaking, a hole appearing at the base of the fingernail may be caused by vitamin deficiency, traumatic or mechanical injury, onychomycosis (fungal nail infection), psoriasis, or subungual keratolysis. Patients are advised to seek timely medical attention for appropriate diagnosis and treatment. Specific causes are analyzed as follows:

1. Vitamin Deficiency

When the body lacks vitamins such as vitamin A or minerals like potassium, systemic malnutrition may occur, causing the nails to become brittle. Some patients may experience frequent nail cracking, whitening, or even rotting at the nail base. In such cases, it is recommended that patients increase their intake of foods rich in vitamins. Additionally, under a doctor’s guidance, oral supplements such as vitamin A soft capsules or vitamin C tablets may be taken for treatment.

2. Traumatic or Mechanical Injury

Injuries due to trauma or mechanical damage—such as impact, compression, or excessive trimming—can cause damage to the nail matrix, leading to rotting at the nail base and the formation of a hole. Such injuries may result in indentations or protrusions on the nail surface and may be accompanied by pain, bleeding, or infection. Patients are advised to follow medical advice and take anti-inflammatory and analgesic medications, such as amoxicillin capsules or diclofenac sodium sustained-release tablets.

3. Onychomycosis (Fungal Nail Infection)

If hygiene is neglected or the nail is infected by fungi, various digestive enzymes may be released locally, eroding the nail tissue. This can lead to localized nail necrosis, rotting at the nail base, and scaling. Patients with this condition may use topical medications such as mupirocin ointment or clotrimazole cream to relieve symptoms.

4. Psoriasis

Psoriasis is associated with genetic factors, trauma, and long-term exposure to chemical substances. It causes immune system dysfunction and sterile inflammation, which irritates local tissues and leads to symptoms such as holes at the nail base, nail cracking, and peeling. Patients may use medications such as compound acetic acid dexamethasone cream or hydrocortisone butyrate cream to alleviate symptoms.

5. Subungual Keratolysis

Subungual keratolysis is a rare inherited skin disorder. Patients typically develop crusted, erosive pits on the nails. These pits can make the nails fragile and prone to breaking, resulting in hole-like defects. Under medical supervision, patients may apply topical treatments such as urea ointment or tretinoin cream.

In addition, a hole at the base of the fingernail may also be related to paronychia or common warts. If the condition worsens, patients should promptly consult a doctor, undergo relevant examinations, and follow prescribed treatments to avoid delaying recovery.