Incidence and causes of heparin-induced skin lesions.
BACKGROUND
Little is known about the incidence and causes of heparin-induced skin lesions. The 2 most commonly reported causes of heparin-induced skin lesions are immune-mediated heparin-induced thrombocytopenia and delayed-type hypersensitivity reactions.


METHODS
We prospectively examined consecutive patients who received subcutaneous heparin (most often enoxaparin or nadroparin) for the presence of heparin-induced skin lesions. If such lesions were identified, we performed a skin biopsy, platelet count measurements, and antiplatelet-factor 4 antibody and allergy testing.


RESULTS
We enrolled 320 patients. In total, 24 patients (7.5%, 95% confidence interval [CI] 4.7%-10.6%) had heparin-induced skin lesions. Delayed-type hypersensitivity reactions were identified as the cause in all 24 patients. One patient with histopathologic evidence of delayed-type hypersensitivity tested positive for antiplatelet-factor 4 antibodies. We identified the following risk factors for heparin-induced skin lesions: a body mass index greater than 25 (odds ratio [OR] 4.6, 95% CI 1.7-15.3), duration of heparin therapy longer than 9 days (OR 5.9, 95% CI 1.9-26.3) and female sex (OR 3.0, 95% CI 1.1-8.8).


CONCLUSIONS
Heparin-induced skin lesions are relatively common, have identifiable risk factors and are commonly caused by a delayed-type hypersensitivity reaction (type IV allergic response).
Schindewolf
Marc
M
Department of Internal Medicine, Division of Angiology, Hospital of the Johann Wolfgang Goethe University, Frankfurt am Main, Germany.
Schwaner
Svantje
S
Wolter
Manfred
M
Kroll
Hartmut
H
Recke
Andreas
A
Kaufmann
Roland
R
Boehncke
Wolf-Henning
WH
Lindhoff-Last
Edelgard
E
Ludwig
Ralf J
RJ
D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D003875:Drug Eruptions / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006493:Heparin / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D013921:Thrombocytopenia / Q000139:chemically induced / Q000150:complications* / Q000453:epidemiology
D000925:Anticoagulants; D006493:Heparin