Causes of Spontaneous Bruising

Bleeding Disorders

The American Academy of Pediatrics notes that Von Willebrand disease (VWD) is the most common inherited bleeding disorder with a prevalence of approximately 1 in 1000 people, presenting with mucocutaneous bleeding and easy bruising 1
Hemophilia (Factor VIII or IX deficiency) can cause significant bruising and bleeding even with mild deficiencies, particularly concerning in males 2
Factor XIII deficiency is not detected by standard PT/aPTT screening tests but can cause significant bruising 1
Immune thrombocytopenia (ITP) is a transient, often self-resolving bleeding disorder characterized by low platelet count 3
Platelet function disorders can present with bruising and mucocutaneous bleeding; diagnosis requires specialized testing such as platelet aggregation studies 1

Vitamin Deficiencies

Vitamin K deficiency is particularly important in infants who haven't received vitamin K prophylaxis at birth, and presents with prolonged PT and possibly aPTT 3

Vascular and Connective Tissue Disorders

Arteriovenous malformations can cause localized bleeding and bruising 4
Senile purpura is caused by thinning of blood vessels and skin with aging 5

Other Medical Causes

Liver disease/cirrhosis can lead to decreased production of clotting factors and spontaneous bruising 6
Disseminated intravascular coagulation (DIC) can cause any type of bruising/bleeding, including intracranial hemorrhage 2
Malignancies and infiltrative disorders can cause thrombocytopenia or coagulation abnormalities 7
Medications such as anticoagulants, antiplatelets, NSAIDs, steroids, and some antibiotics can increase bruising tendency 8

Diagnostic Approach

Initial screening tests should include complete blood count with platelet count to evaluate for thrombocytopenia 1
Prothrombin time (PT) and activated partial thromboplastin time (aPTT) can detect most factor deficiencies but not VWD or factor XIII deficiency 1
Fibrinogen concentration and thrombin time can detect defects of fibrinogen 1

Special Considerations

In children, the pattern and location of bruising must be carefully evaluated to distinguish between bleeding disorders and potential abuse 7
In adults with cirrhosis, abnormal laboratory tests (INR, APTT, platelet count, fibrinogen) are common but don't necessarily predict spontaneous bleeding 6

Easy Bruising with Normal Platelet Count in a Young Female

Understanding the Clinical Picture

The elevated platelet count (410,000/μL) in a patient with easy bruising suggests reactive thrombocytosis, which requires further investigation into platelet function 9

Laboratory Testing Algorithm

Fibrinogen level testing is necessary to detect fibrinogen defects, as part of the initial diagnostic workup 10
PT (Prothrombin Time) and aPTT (Activated Partial Thromboplastin Time) do not detect von Willebrand disease or mild platelet disorders, making additional testing necessary 10

Common Pitfalls to Avoid

Assuming normal PT/aPTT rules out bleeding disorders is incorrect, as these tests miss von Willebrand disease, Factor XIII deficiency, and platelet function disorders 10
Overlooking mild hemophilia, such as mild Factor VIII or IX deficiency, can still cause significant bleeding, even if aPTT is not prolonged 10

Easy Bruising with Normal Platelet Count: Diagnostic Approach

Initial Laboratory Evaluation

The American Society of Hematology recommends PT, aPTT, and fibrinogen testing in patients with easy bruising and a normal platelet count, as these tests can detect most factor deficiencies, although they may miss von Willebrand disease and Factor XIII deficiency 11, 12
A peripheral blood smear should be reviewed to assess platelet morphology and identify altered platelet size/structure that may suggest specific inherited platelet function disorders 13

Differential Diagnoses

Von Willebrand disease is the most common inherited bleeding disorder and presents with mucocutaneous bleeding and easy bruising, but is not reliably detected by PT/aPTT screening, requiring specific VWD testing including VWF antigen, VWF ristocetin cofactor activity, and Factor VIII coagulant activity 11, 12
Inherited platelet function disorders can present with normal platelet count but abnormal platelet function, requiring specialized testing including light transmission aggregometry and flow cytometry to assess major platelet surface glycoproteins 13

Diagnostic Algorithm

If PT and aPTT are normal, there is a high likelihood of von Willebrand disease or platelet function disorder, and VWD-specific testing should be performed 11, 12
If both PT and aPTT are prolonged, evaluation for liver disease, vitamin K deficiency, or disseminated intravascular coagulation (DIC) is necessary 12, 14

Referral to Hematology

Referral to hematology is indicated when specialized testing, such as platelet function studies, VWD multimer analysis, or Factor XIII assay, is needed 11, 13

Bleeding Disorders with Normal Platelet Count

Diagnostic Considerations

Patients can have significant bleeding manifestations, including easy bruising, with normal or even elevated platelet counts due to qualitative platelet defects, as noted by the American Academy of Pediatrics and the Leukemia society 15, 16
Acquired von Willebrand syndrome can occur in patients with high platelet counts and causes bleeding despite thrombocytosis, according to the Leukemia society 16

Preoperative Evaluation

Before any surgical procedure, patients with easy bruising should be screened with CBC, platelet count, platelet function study, and von Willebrand screen, even if platelet count is normal, as recommended by the American Academy of Pediatrics 15
Treatment of acquired von Willebrand syndrome with desmopressin or von Willebrand factor concentrates may be necessary, as suggested by the Leukemia society 16
Platelet dysfunction typically improves within 2-4 weeks of treating underlying conditions, according to the Leukemia society 16

Evaluation and Management of Easy Bruising

Laboratory Considerations

The American Academy of Pediatrics notes that coagulation tests are very sensitive to specimen handling and should be performed in experienced laboratories, as inappropriate handling commonly leads to false-positive results 17
The American Academy of Pediatrics also notes that aPTT can be falsely prolonged with lupus anticoagulant or in Factor XII deficiency (which does not indicate a true bleeding disorder) 17
In children with intracranial hemorrhage concerning for abuse, laboratory testing suggestive of a bleeding disorder does not eliminate abuse from consideration; follow-up evaluation after change in home setting can provide valuable information 17
If blood product transfusions have been given, delay screening for bleeding disorders until elimination of transfused clotting elements 17

Assessment of Bruising Location in Adolescents

Clinical Significance of Bruising Location

In patients around 18 years old, bruises that appear on soft‑tissue areas such as the thighs, upper arms, or trunk are more indicative of an underlying bleeding disorder than bruises over bony prominences that commonly result from normal activity — a distinction highlighted in pediatric clinical guidance 18

Evaluation of Normal aPTT and Bleeding Risk in Older Adults

Interpretation of a Normal aPTT

A normal activated partial thromboplastin time (aPTT) effectively rules out clinically significant deficiencies of the intrinsic coagulation factors (VIII, IX, XI) and the common pathway factors (II, V, X) in an elderly patient. American Society of Anesthesiologists guidance supports this exclusion. 19
Despite a normal aPTT, von Willebrand disease (VWD) and platelet‑function disorders can still be present; these conditions are not detected by routine aPTT testing. American Society of Hematology notes this limitation. 20

Limitations of PT/INR and aPTT in Detecting Bleeding Disorders

Normal PT/INR and aPTT values do not reliably exclude bleeding disorders such as VWD, factor XIII deficiency, or qualitative platelet defects, emphasizing the need for targeted hemostatic testing when clinical suspicion persists. American Society of Hematology highlights this diagnostic gap. 20

Recommended Hemostatic Work‑up When aPTT Is Normal

For patients with unexplained bruising and a normal aPTT, the American Society of Hematology recommends specific laboratory evaluation for VWD, including VWF antigen, ristocetin cofactor activity, and factor VIII activity assays. These tests are essential because standard PT/aPTT panels fail to identify VWD. 20
Comprehensive coagulation assessment should also incorporate PT/INR measurement to evaluate the extrinsic pathway and hepatic synthetic function, as advised by both the American Society of Anesthesiologists and the American Society of Hematology. [19][20]

Lichen Sclerosus–Related Ecchymosis in Children

Clinical Presentation

Ecchymosis can be prominent in pre‑pubertal children with anogenital lichen sclerosus, often mimicking signs of sexual abuse. The lesions appear as striking bruises in the genital area, which may lead to misinterpretation without careful assessment. [21][22]
Typical lichen sclerosus lesions are porcelain‑white papules or plaques accompanied by areas of ecchymosis located in the interlabial sulci, labia minora, and perineal body. These characteristic skin changes help differentiate the condition from other causes of bruising. [21][22]
Perianal involvement is reported in roughly 30 % of female cases and frequently presents with constipation due to painful fissuring. This association underscores the need to evaluate bowel habits when lichen sclerosus is suspected. 21
Lichen sclerosus and sexual abuse are not mutually exclusive; the disease can exhibit the Koebner phenomenon, producing lesions at sites of trauma. Consequently, the presence of lichen sclerosus does not rule out concurrent abuse. [21][22]
Red‑flag features suggesting possible abuse in children with lichen sclerosus include: older pre‑pubertal age, poor response to standard therapy, co‑existing sexually transmitted infections, or additional clinical signs of maltreatment. These criteria aid clinicians in deciding when to initiate abuse investigations. 22