What are the possible causes of excessive bruising and pruritus in a teenage female?

Excessive Bruising and Itching in a Teenage Girl

In a teenage girl presenting with excessive bruising and itching, immediately order a complete blood count with differential, ferritin levels, liver function tests, and platelet count to evaluate for iron deficiency, hematological disorders (particularly immune thrombocytopenic purpura), and systemic causes of pruritus. 1, 2, 3

Initial Diagnostic Approach

Critical Laboratory Workup

• Complete blood count with differential and platelet count is essential to identify thrombocytopenia, which commonly presents as easy bruising in teenage females and may be due to immune thrombocytopenic purpura (ITP) 4
• Ferritin and iron studies must be obtained, as iron deficiency is the most common systemic cause of pruritus (25% of patients with systemic disease causing itch) and causes both easy bruising and generalized itching 1, 2
• Liver function tests, total bilirubin, and serum bile acids are required to exclude cholestatic liver disease, which causes severe pruritus particularly affecting palms and soles, worse at night 2, 3
• Thyroid function tests should be included if clinical features suggest thyroid disease 2

Key Historical Elements to Elicit

• Medication history including over-the-counter drugs, herbal remedies, and supplements, as 12.5% of drug reactions present with pruritus without rash, and certain medications can affect platelet function 1, 3
• Bleeding history including excessive bleeding after dental procedures, circumcision, or other surgeries, heavy menstrual periods, epistaxis, or bleeding from the umbilical stump (if known), which suggests an underlying bleeding disorder 5
• Family history of bleeding disorders or easy bruising, as autoimmune thrombocytopenic purpura has a genetic predisposition and occurs more commonly in females 4
• Timing and distribution of itching: worse at night suggests cholestatic disease; aquagenic (water-triggered) suggests polycythemia vera 2, 3

Physical Examination Focus

• Location of bruising: buttocks, ears, and genitals have higher specificity for abuse and must be carefully evaluated, though bleeding disorders can cause bruising in any location 5
• Pattern of bruising: patterned bruising (e.g., slap marks, loop marks) strongly suggests abuse and does not require bleeding disorder workup 5
• Skin examination for subtle findings: look for porcelain-white papules or plaques (lichen sclerosus), petechiae, or purpuric lesions 1
• Signs of systemic disease: jaundice, hepatosplenomegaly, lymphadenopathy 5, 6

Differential Diagnosis by Priority

Hematological Causes (Most Likely Given Combined Symptoms)

• Immune thrombocytopenic purpura (ITP) is the leading consideration in a teenage female with easy bruising, as it has female predominance and commonly presents with cutaneous bruising 4
• ITP patients may have antiplatelet antibody-induced platelet functional defects causing the "easy bruising syndrome" even with normal or near-normal platelet counts 4
• Iron deficiency causes both easy bruising and generalized pruritus, with complete resolution of itching shortly after iron replacement begins 1, 2
• Polycythemia vera should be considered if aquagenic pruritus is present; order JAK2 V617F mutation testing 2, 3

Systemic Causes of Pruritus

• Cholestatic liver disease causes severe pruritus predominantly affecting palms and soles, worsening at night, and requires bile acid measurement for definitive diagnosis 2, 3
• Chronic kidney disease causes uremic pruritus and can be associated with easy bruising; assess urea and electrolytes 2, 3
• Thyroid disorders (both hyper- and hypothyroidism) can cause pruritus 2, 3
• HIV infection should be considered with appropriate risk history, as it causes severe pruritus correlating with viral load 5, 3

Dermatological Causes

• Lichen sclerosus commonly presents with severe itch as the primary symptom, particularly worse at night, and may have subtle white changes easily missed on examination 1
• Scabies must always be considered, as it presents with severe pruritus and minimal visible signs, particularly in immunocompromised patients 5, 3

Drug-Induced Causes

• Opioid-induced pruritus affects 2-10% of patients on oral opioids 3
• Statin-induced cholestatic hepatitis causes pruritus as a cardinal symptom 2
• Discontinue suspected causative medications immediately 1

Important Consideration: Child Abuse

• While bleeding disorders can cause bruising in locations considered suspicious for abuse, a thorough evaluation for possible abuse must occur simultaneously with medical workup 5
• Interview the patient away from potential offending caregivers if possible 5
• If the constellation of findings is strongly consistent with abuse (e.g., patterned injuries with credible disclosure), further laboratory investigation for bleeding disorders may not be warranted 5

Treatment Algorithm Based on Diagnosis

If Iron Deficiency Identified

• Initiate iron replacement therapy immediately, which leads to rapid symptom resolution of both bruising tendency and pruritus 1, 2

If ITP Diagnosed (Platelet Count <40,000/mm³ with Purpura)

• Corticosteroids are first-line treatment, with approximately 50% response rate 4
• Treatment goal is maintaining platelet count >40,000/mm³ to keep patient free of purpura, not necessarily normalizing platelet count 4
• Splenectomy is successful in 65-75% of steroid-refractory patients 4

If Cholestatic Pruritus Confirmed

• Rifampin 150 mg twice daily is first-line treatment for hepatic pruritus 2
• Cholestyramine 9 g daily is second-line treatment 2

Symptomatic Treatment for Pruritus (While Awaiting Diagnosis)

• Emollients and moisturizers should be applied at least twice daily as first-line treatment for all pruritus 2
• Refrigerated menthol and pramoxine for symptomatic relief 2
• Gabapentin 300-1200 mg daily in divided doses for severe refractory pruritus 2
• Avoid long-term sedating antihistamines due to dementia risk, especially in elderly patients 2

Critical Pitfalls to Avoid

• Do not dismiss subtle findings: lichen sclerosus may present with minimal visible changes but severe symptoms; iron deficiency is easily treatable but frequently overlooked 1, 2
• Do not delay iron studies: iron deficiency is a common, treatable cause of both symptoms 1, 2
• Do not overlook medication review: drug-induced pruritus commonly occurs without visible changes 1, 3
• Do not assume all bruising is benign: maintain high suspicion for abuse while simultaneously evaluating for medical causes 5
• Do not confuse excoriations from scratching with primary rash: the underlying cause may still be systemic disease 1
• Do not delay bile acid testing if cholestatic disease is suspected, as this is the definitive diagnostic test 3

When to Escalate Care

• Refer to hematology if platelet count <40,000/mm³, abnormal coagulation studies, or suspected bleeding disorder 4
• Refer to dermatology if diagnosis remains uncertain after initial workup or if skin biopsy is needed 2
• Refer to hepatology if significant hepatic impairment or persistent elevation of liver enzymes 2
• Refer to child protective services if abuse is suspected based on history, physical examination, or pattern of injuries 5
• Send to emergency department immediately if hypotension, tachycardia, respiratory distress, severe abdominal pain with jaundice, altered mental status, or rash with fever and mucosal involvement develops 2