15.3 Medication-Induced & Hematologic Atypical Wounds
Key Takeaways
- Warfarin-induced skin necrosis appears about 3 to 5 days after starting warfarin, often without heparin overlap, in fatty areas such as the breasts, thighs, and buttocks; stop warfarin, give vitamin K, anticoagulate with heparin, and consider protein C concentrate or plasma.
- Heparin-induced thrombocytopenia can cause skin necrosis at injection sites, typically 5 to 10 days after heparin exposure; assess with the 4Ts score, stop all heparin, and start a non-heparin anticoagulant such as argatroban, bivalirudin, fondaparinux, or a direct oral anticoagulant.
- Hydroxyurea can cause painful ulcers around the malleoli during long-term therapy that often heal only after the drug is reduced or stopped, while levamisole-adulterated cocaine causes retiform purpura and necrosis of the ears and cheeks, often with neutropenia and positive ANCA.
- Hematologic causes of ulcers include sickle cell disease (malleolar ulcers), cryoglobulinemia, polycythemia vera and essential thrombocythemia, livedoid vasculopathy, and inherited or acquired clotting disorders; send cryoglobulin samples warm at 37°C.
- Chemotherapy extravasation needs agent-specific care: dexrazoxane for anthracyclines, hyaluronidase with warm compresses for vinca alkaloids, and phentolamine for vasopressor extravasation.
15.3 Medication-Induced & Hematologic Atypical Wounds
Core Clinical Principle: When a wound does not match the usual venous, arterial, pressure, or diabetic patterns, look at the medication list and the blood. Drugs and blood disorders can cause skin necrosis within days or chronic ulcers that heal only when the cause is removed.
The CWSP outline lists atypical wounds, including malignancy and medication-induced wounds, under Etiological Considerations. Malignant wounds and inflammatory ulcers are covered in their own sections; this section focuses on drugs and hematologic disease.
Medication-Induced Skin Necrosis
| Condition | Timing and Setting | Appearance | Management |
|---|---|---|---|
| Warfarin-induced skin necrosis | Days 3 to 5 after starting warfarin, often with a loading dose and no heparin overlap; linked to protein C deficiency | Painful red patches that become hemorrhagic bullae and black necrosis in fatty areas (breasts, thighs, buttocks, abdomen) | Stop warfarin, give vitamin K, anticoagulate with heparin, consider protein C concentrate or fresh frozen plasma; surgical care of necrosis |
| Heparin-induced thrombocytopenia (HIT) skin necrosis | Usually 5 to 10 days after heparin exposure (sooner with recent exposure) | Necrosis at subcutaneous injection sites; platelet fall of more than 50%; venous or arterial thrombosis | 4Ts score, stop all heparin including flushes, start a non-heparin anticoagulant; confirm with PF4 antibody and functional assays |
| Vasopressor-related necrosis | High-dose norepinephrine, vasopressin, or other pressors in shock | Symmetric acral necrosis of fingers, toes, ears, nose | Minimize pressor dose when possible; allow demarcation before amputation |
| Nicolau syndrome (embolia cutis medicamentosa) | Minutes to hours after intramuscular or intra-articular injection | Severe pain, livedoid patch, then necrosis at the injection site | Supportive wound care, pain control, debridement when demarcated |
Drug-Associated Ulcers and Wounds
- Hydroxyurea: Painful, shallow ulcers around the malleoli or on the legs during long-term therapy for myeloproliferative disorders or sickle cell disease. They resist standard care and often heal only after dose reduction or stopping the drug, in consultation with hematology.
- Methotrexate: Toxicity can erode psoriatic plaques or cause mucosal and skin ulcers, especially with kidney impairment or dosing errors (daily instead of weekly); treat with leucovorin rescue.
- Levamisole-adulterated cocaine: Retiform purpura and necrosis of the ears, cheeks, and nose, often with neutropenia and positive ANCA (commonly atypical patterns). Stopping cocaine use is essential.
- Xylazine-associated wounds: Xylazine, a veterinary sedative mixed into the illicit fentanyl supply, is linked to severe wounds at and away from injection sites. The FDA issued a warning in 2022, and the federal government declared fentanyl combined with xylazine an emerging threat in 2023. Care focuses on nonjudgmental wound care, harm reduction, and treatment of substance use; naloxone reverses opioids but not xylazine.
- Nicorandil: Associated with painful oral, anal, and skin ulcers that heal after stopping the drug (used mainly outside the United States).
- Drugs that impair healing: Systemic corticosteroids; VEGF inhibitors such as bevacizumab (labeling advises stopping at least 28 days before elective surgery and waiting at least 28 days after surgery and until the wound is healed); mTOR inhibitors (sirolimus, everolimus); antiproliferative chemotherapy; and some biologic immunosuppressants.
Extravasation Injuries
| Agent Type | Examples | Specific Measures |
|---|---|---|
| Anthracyclines | Doxorubicin, daunorubicin | Stop infusion, aspirate, cold compresses; intravenous dexrazoxane within 6 hours (stop cooling beforehand) |
| Vinca alkaloids | Vincristine, vinblastine | Hyaluronidase injection and warm compresses to disperse the drug |
| Vasopressors | Norepinephrine, dopamine | Local phentolamine injection |
| Other irritants and vesicants | Calcium salts, potassium, hypertonic dextrose, contrast media, some antibiotics | Stop infusion, elevate, consider hyaluronidase; surgical consult for compartment symptoms or skin loss |
Hematologic Causes of Ulcers
| Condition | Key Features | Workup and Treatment |
|---|---|---|
| Sickle cell disease | Painful ulcers over the malleoli, most common in HbSS; slow healing and frequent recurrence | Hemoglobin electrophoresis; compression if perfusion allows, wound care, hematology co-management (transfusion strategies, disease-modifying therapy) |
| Thalassemia and hereditary spherocytosis | Leg ulcers from chronic hemolysis and anemia | CBC, smear, hemolysis markers |
| Cryoglobulinemia | Type I (monoclonal): occlusive retiform purpura and acral necrosis; mixed types II and III: vasculitis, often with hepatitis C | Cryoglobulins drawn and transported warm at 37°C, complement levels, hepatitis C testing, serum protein electrophoresis |
| Polycythemia vera and essential thrombocythemia | Erythromelalgia, acral ischemia, ulcers | CBC, JAK2 mutation testing; low-dose aspirin, cytoreduction |
| Livedoid vasculopathy | Painful recurrent ulcers around the ankles that heal as white stellate scars (atrophie blanche), often worse in summer | Biopsy showing vessel thrombi without true vasculitis; thrombophilia testing; antiplatelet or anticoagulant therapy (for example, rivaroxaban off-label) |
| Protein C or S deficiency, antiphospholipid syndrome, DIC | Purpura fulminans, retiform purpura, necrosis | Coagulation studies, antiphospholipid antibodies, protein C and S levels; anticoagulation and treatment of the cause |
Retiform Purpura: A Red Flag
Net-like, branching purpura with necrosis signals blocked small vessels from thrombosis, emboli, calciphylaxis, cryoglobulins, or vasculitis. It calls for prompt biopsy (including the purpuric edge), coagulation and hematologic studies, and a medication and drug use history.
Clinical Traps
Trap 1: Continuing Warfarin Through Early Necrosis
New painful purpura in fatty tissue days after starting warfarin is an emergency. Stop warfarin, give vitamin K, and switch to heparin.
Trap 2: Debriding a Hydroxyurea Ulcer Without Addressing the Drug
Repeated debridement and advanced dressings rarely help while the patient remains on hydroxyurea. Discuss dose changes with hematology.
A 63-year-old woman started warfarin with a loading dose 4 days ago for a new DVT, without heparin overlap. She now has severe pain and a large purple patch with hemorrhagic bullae and central black necrosis on her left breast and thigh. What is the most appropriate management?
A 66-year-old man with polycythemia vera has taken hydroxyurea for 6 years. He has two shallow, very painful ulcers over the lateral malleolus that have not improved after 5 months of debridement, moist dressings, and compression. His ABI is 1.05, and biopsy excluded malignancy and vasculitis. Which step is most likely to lead to healing?
A 38-year-old man presents with painful, net-like purple patches and necrosis on both ears and cheeks. Laboratory tests show an absolute neutrophil count of 900/µL and positive ANCA. He reports recent cocaine use. What is the most likely cause?