Subungual Hematoma: Symptoms, Types, Causes and Treatment

Subungual hematoma—a term that may sound daunting—simply refers to bleeding and blood accumulation under a fingernail or toenail. It’s a common nail emergency, often striking after a traumatic injury like slamming a finger in a door or dropping a heavy object on a toe. While typically benign, the condition is known for its sharp pain, distinctive discoloration, and the anxiety it can cause, especially when its appearance mimics more serious conditions. In this comprehensive guide, we’ll explore the symptoms, types, causes, and best treatment strategies for subungual hematoma, bringing clarity and reassurance to anyone experiencing this uncomfortable nail injury.

Symptoms of Subungual Hematoma

Recognizing the symptoms of a subungual hematoma is crucial for seeking timely care and distinguishing it from other nail disorders. The condition is primarily characterized by dramatic changes in nail color and intense pain, but subtle variations can occur depending on the injury’s cause and severity.

Symptom	Description	Severity	Source
Discoloration	Reddish, reddish-black, brown, or black spot	Mild to severe	1, 5
Pain	Sharp, throbbing, often severe	Usually severe	4, 6
Swelling	Swelling of nail, fingertip or toe	Variable	4, 6
Nail Changes	Onycholysis, deformity, infection risk	Possible	4, 7

Table 1: Key Symptoms

Common Clinical Features

Subungual hematoma typically begins with a vivid discoloration beneath the nail. This coloration can range from bright red to deep black, depending on the age of the hematoma and the amount of blood trapped under the nail plate. The color often changes over days from red to brown or black as the blood ages and breaks down 1, 5.

Pain and Pressure

Perhaps the most distinctive and distressing symptom is intense pain. The buildup of blood creates pressure between the nail plate and the sensitive nail bed, resulting in throbbing pain that can be “exquisitely” severe, especially in the hours immediately following the injury 4, 6. This pain may be constant or worsen when the digit is used or touched.

Additional Nail and Soft Tissue Changes

Other symptoms include:

• Swelling of the fingertip or toe
• Tenderness to touch
• Possible separation of the nail from its bed (onycholysis)
• In some cases, infection or nail deformity can develop, particularly if the hematoma is large or not promptly treated 4, 7.

Risk of Misdiagnosis

Importantly, the pigment changes seen in subungual hematoma can mimic other conditions, including subungual melanoma. This overlap underscores the importance of a careful clinical evaluation and, if in doubt, the use of dermoscopy and follow-up to confirm the diagnosis 1, 5.

Types of Subungual Hematoma

Not all subungual hematomas look or behave the same. Understanding the types can help guide diagnosis and treatment, and can also rule out more serious underlying conditions.

Type	Key Feature	Typical Appearance	Source
Acute	Recent trauma, sudden	Red to black spot	1, 4
Chronic	Repeated trauma, slower	Brown-black, fading	6
Subcorneal	Just under nail surface	Red-brown, globular	5

Table 2: Types of Subungual Hematoma

Acute Subungual Hematoma

This is the classic form, developing quickly after a single traumatic event (e.g., a crush injury). It is marked by sudden pain and a rapidly appearing dark area under the nail. The color is often red, purple, or black, and the pain can be severe due to sudden pressure increase 1, 4.

Chronic Subungual Hematoma

Chronic forms develop over time due to repeated minor trauma, such as from running, wearing tight shoes, or repetitive sports activities. The discoloration may be less vivid and the pain less intense. Instead, patients might notice gradual darkening or deformity of the nail, sometimes with pigmentary changes or mild discomfort 6.

Subcorneal Hematoma

This less common subtype involves bleeding just beneath the superficial layers of the nail. Clinically, it can mimic acral melanoma, with color patterns ranging from red to brown to black. Dermoscopy often reveals a homogenous pattern, globules, and sometimes a parallel ridge pattern. The “scratch test” can help distinguish it from more serious pathology 5.

Causes of Subungual Hematoma

Understanding the underlying causes of subungual hematoma helps in both prevention and management. While trauma is the leading factor, other systemic and external contributors exist.

Cause	Mechanism	Typical Context	Source
Acute Trauma	Direct blow, crush, or impact	Sports, accidents	4, 6
Chronic Trauma	Repetitive minor injury	Athletes, runners	6
Systemic	Medications, diseases, aging	Elderly, comorbid	4
Iatrogenic	Medical/surgical interventions	Nail treatments	4

Table 3: Common Causes of Subungual Hematoma

Acute Trauma

The majority of subungual hematomas result from a direct physical blow to the nail, such as:

• Slamming a finger in a door
• Dropping an object on the toe
• Sports injuries (e.g., kicking a ball, being stepped on) 4, 6

This sudden force causes blood vessels in the nail bed to rupture, leading to blood pooling beneath the nail plate.

Chronic and Repetitive Trauma

Chronic subungual hematomas are linked to activities that repeatedly stress the nail:

• Long-distance running
• Ill-fitting shoes
• Manual labor or repetitive use of tools 6

Over time, these micro-injuries can damage the nail bed, resulting in persistent or recurring hematomas.

Systemic and Non-Traumatic Factors

Though less common, subungual hematoma can also be linked to:

• Systemic diseases affecting blood vessels or clotting
• Medication side effects (e.g., anticoagulants)
• Drug reactions
• Age-related changes in nail structure 4

Iatrogenic and Other Causes

Occasionally, medical procedures (e.g., treatments or surgeries involving the nail) or aggressive manicures can result in subungual bleeding 4.

Treatment of Subungual Hematoma

Prompt and appropriate treatment is essential to relieve pain, prevent complications, and minimize nail deformity. Treatments vary depending on the hematoma’s size, severity, and presence of complications like fractures.

Treatment	Indication	Main Benefit	Source
Trephination	Painful, large, acute hematoma	Rapid pain relief	7, 11
Needle Drainage	Smaller hematoma, thin nails	Minimally invasive	11
Conservative	Small, painless, minor trauma	Observation, safety	7
Surgery	Severe, complex, or with fracture	Nail bed repair	7, 4

Table 4: Treatment Approaches

Trephination (Nail Drilling or Burning)

The gold standard for painful subungual hematoma is nail trephination. This involves creating a small hole in the nail plate (using a heated needle, cautery, or drill) to allow trapped blood to escape, instantly relieving pressure and pain. It is safe and effective, even with larger hematomas or in the presence of distal phalangeal fractures, provided the fracture is not open or grossly unstable 7.

• Trephination is quick and well-tolerated
• No need for nail removal or suturing in simple cases
• Infection and major deformity are rare if performed correctly 7

Fine Needle Drainage

For smaller hematomas, especially in toenails where access is more challenging, using an ultra-fine (29-gauge) insulin syringe can be a practical alternative. This method is fast, simple, and well-tolerated, especially for less severe cases or pediatric patients 11.

Conservative Management

If the hematoma is small, painless, and not causing significant discomfort, no intervention may be required. The blood will gradually grow out with the nail over weeks to months. Conservative observation is safe and avoids unnecessary procedures 7.

Surgical Repair

In rare cases, especially when there is extensive nail bed laceration, avulsion, or associated fracture, surgical intervention may be necessary. This involves removing the nail plate and repairing the nail bed with fine sutures. Nevertheless, for most simple hematomas—even large ones—such invasive procedures are not needed 7, 4.

Complications and Follow-Up

Patients should be warned about possible complications:

• Onycholysis (nail detachment)
• Transient or permanent nail deformity
• Infection

The risk is low when treatment is timely and appropriate. Follow-up is important to monitor for signs of infection or abnormal nail growth 4, 7.

Conclusion

Subungual hematoma, while often dramatic and painful, is a familiar and treatable nail injury. Timely recognition and proper management can prevent complications and speed recovery. Here’s what you need to remember:

• Symptoms include rapid-onset pain and discoloration, with risk of nail deformity or infection if untreated 1, 4, 6.
• Types vary from acute to chronic to subcorneal, each with distinct clinical and dermoscopic features 1, 5, 6.
• Causes are usually traumatic, but systemic factors and repetitive injury can play a role 4, 6.
• Treatment is guided by severity: trephination or needle drainage for painful cases, conservative management for minor ones, and surgery only for complex injuries 7, 11, 4.

By understanding these aspects, patients and clinicians alike can navigate subungual hematoma confidently, ensuring rapid relief and healthy nail regrowth.