Pain when pressing on a fingernail or toenail is medically known as onychalgia. This symptom occurs because the nail unit is highly innervated, meaning it is richly supplied with nerve endings. External pressure compresses the sensitive soft tissues and nerve structures beneath the rigid nail plate, causing discomfort. Causes generally involve external forces, inflammatory processes, or conditions localized beneath the nail itself.
Common Mechanical and Structural Reasons
The most frequent reasons for a painful nail when pressed involve direct physical stress or minor structural irregularities. Repetitive microtrauma, such as constant tapping on a keyboard or pressure from ill-fitting shoes, can sensitize the nail unit over time. This ongoing irritation is amplified when deliberate pressure is applied. Improper trimming is another common mechanical cause, often leading to an ingrown nail (onychocryptosis). This occurs when the nail edge pierces the surrounding skin of the nail fold, creating a painful point of irritation. Minor injuries causing bleeding or swelling can also heighten sensitivity until the tissue heals.
Inflammatory and Infectious Causes
When the pain is accompanied by warmth, redness, and swelling, an inflammatory or infectious process is likely making the area hypersensitive to pressure. Paronychia, an infection of the skin around the nail fold, is a primary example. This condition, which can be acute (bacterial) or chronic (often fungal), causes the nail fold tissue to swell. Swelling creates increased internal pressure within the limited space of the nail fold, activating pain-sensing nerve receptors. External pressure then compresses the swollen, inflamed tissue further, resulting in a sharp increase in pain. Chronic fungal infections (onychomycosis) can also cause the nail plate to thicken, increasing pressure on the underlying nail bed and making the area more sensitive.
Internal Conditions Affecting the Nail Bed
Pain upon pressure can also originate from lesions or changes directly beneath the nail plate. A subungual hematoma, a collection of blood under the nail following trauma, is a common cause. The rigid nail plate traps the blood, causing significant pressure on the sensitive nail bed, and any external force exacerbates this throbbing pain. The discoloration beneath the nail, often purple or black, signals this issue. More rarely, a small, benign tumor can cause localized pressure pain. A glomus tumor is a tiny vascular growth in the nail bed associated with intense, pinpoint tenderness and hypersensitivity to cold temperatures. The pain is often disproportionate to the lesion’s size; even the slightest touch (Love’s sign) can elicit severe pain. Chronic skin diseases, such as nail psoriasis, can also increase the nail bed’s sensitivity to pressure.
When to Seek Professional Guidance
While many instances of nail pain resolve with simple home care, certain signs indicate the need for professional evaluation. Consult a healthcare provider if the pain is severe, persistent, or interferes with daily activities. Signs of a spreading infection, such as pus discharge, increasing redness or warmth, or red streaks extending up the limb, warrant prompt attention. Additionally, any unexplained change in nail color or shape, or intense, throbbing pain that wakes you from sleep, should be evaluated to rule out serious internal conditions.