What is the differential diagnosis of splinter hemorrhages?

Differential Diagnosis of Splinter Hemorrhages

Splinter hemorrhages are most commonly caused by trauma, but clinicians must systematically exclude infectious endocarditis, vasculitis, and other systemic conditions before attributing them to benign or idiopathic causes. 1

Primary Etiologic Categories

Traumatic Causes (Most Common)

• Direct nail trauma is the leading cause of splinter hemorrhages, including occupational injury, repetitive microtrauma, and unrecognized minor injuries 2, 1
• Chronic repetitive trauma can occur in healthy individuals without conscious awareness of injury, particularly affecting toenails in 93.7% of cases involving the first toenail 3

Infectious Causes

• Infective endocarditis remains the most critical diagnosis to exclude, as it carries significant morbidity and mortality if missed 1
• Systemic infections of various types can manifest with splinter hemorrhages as part of embolic phenomena 1

Vasculitic and Autoimmune Conditions

• Systemic vasculitis represents an important category requiring urgent evaluation 1
• Antiphospholipid syndrome and other thrombotic disorders should be considered 1
• Systemic lupus erythematosus and related connective tissue diseases 1

Dermatologic Conditions

• Psoriasis is a common dermatologic cause of splinter hemorrhages 1
• Lichen planus can present with nail changes including splinter hemorrhages 1
• Darier disease may show polydactylous involvement with longitudinal erythronychia and associated splinter hemorrhages 4

Drug-Induced

• Medication-related splinter hemorrhages occur with various systemic agents 1
• Specific drug history should be obtained in all cases 2

Neoplastic Causes

• Subungual malignant melanoma must be excluded, particularly in monodactylous presentations in patients over 50 years 4
• Squamous cell carcinoma of the nail unit can present with longitudinal erythronychia and splinter hemorrhages 4
• Glomus tumor may cause monodactylous longitudinal erythronychia with associated splinter hemorrhages 4

Idiopathic/Benign

• Idiopathic atraumatic splinter hemorrhages can occur in completely healthy individuals with spontaneous resolution 2, 5
• Chronic recurrent atraumatic splinter hemorrhages may persist for 6-30 years without underlying systemic disease 5
• In one study, 95.2% of splinter hemorrhages resolved spontaneously within 24 weeks without treatment 3

Clinical Features Guiding Differential Diagnosis

Location and Distribution Pattern

• Distal one-third location is most common but does not exclude systemic disease 5
• Proximal or middle third involvement may suggest more significant pathology 5
• Monodactylous (single nail) involvement warrants consideration of local tumor, trauma, or early systemic disease 4
• Polydactylous (multiple nails) involvement strongly suggests systemic disease, particularly Darier disease, vasculitis, or drug reaction 4

Associated Symptoms

• Pain, burning, or tenderness lasting several days suggests acute hemorrhage but does not differentiate etiology 5
• Asymptomatic presentation is common in both benign and pathologic causes 2

Dermoscopic Characteristics

• Reddish-brown or brown stain with clear boundaries and color fading outward from center, without blue or white structures, suggests benign etiology 3
• Fresh red appearance may indicate active bleeding 1

Essential Workup Algorithm

Initial Assessment

• Detailed trauma history including occupational exposures and repetitive activities 2, 1
• Complete medication review for drug-induced causes 1
• Cardiovascular examination with auscultation for murmurs to exclude endocarditis 1
• Skin examination for signs of psoriasis, lichen planus, or vasculitic lesions 1

Laboratory Evaluation (When Systemic Disease Suspected)

• Blood cultures if fever, new murmur, or constitutional symptoms present 1
• Complete blood count, inflammatory markers (ESR, CRP) for vasculitis screening 1
• Antinuclear antibodies, rheumatoid factor if autoimmune disease suspected 1
• Antiphospholipid antibodies in recurrent cases or thrombotic history 1

When to Biopsy

• Age >50 years with monodactylous presentation to exclude squamous cell carcinoma 4
• Persistent lesions beyond 1 year despite conservative management 3
• Associated longitudinal erythronychia or other concerning nail changes 4
• Progressive or changing appearance suggesting neoplasm 4

Critical Pitfalls to Avoid

• Do not assume trauma without thorough systemic evaluation, especially with multiple nail involvement 1
• Do not delay endocarditis workup in patients with fever, new murmur, or constitutional symptoms—this is a life-threatening diagnosis 1
• Do not biopsy prematurely in young patients with clear trauma history and typical benign features, as 95% resolve within 6 months 3
• Do not ignore polydactylous involvement—this pattern strongly suggests systemic disease requiring comprehensive evaluation 4
• Do not overlook drug history—medication-induced splinter hemorrhages are reversible with drug discontinuation 1

Management Based on Etiology

Benign/Idiopathic Cases

• Observation for 24 weeks is appropriate for typical presentations in healthy individuals 3
• No special treatment required during the first year if spontaneous improvement occurs 3
• Reassurance that spontaneous resolution occurs in the vast majority of cases 2

When Further Investigation Warranted

• Persistence beyond 1 year mandates additional workup 3
• Development of systemic symptoms requires immediate comprehensive evaluation 1
• Multiple nail involvement necessitates systemic disease screening 4