Background: Subcutis calcinosis, characterized by abnormal calcium deposition in the skin, is a rare side effect of calcium containing heparins.
Patients and methods: Two patients with renal failure presented skin lesions after receiving a calcium-containing heparin treatment. The first patient exhibited erythematous nodules on the abdomen and the second a large erythematous induration of the abdomen and nodules on the thighs. Both had normal blood analysis. The diagnosis of subcutis calcinosis was confirmed by the histological exam showing calcium deposit in the dermis and hypodermis. Outcome was unfavourable in one of the patients who developed a superinfection and skin necrosis lesion requiring surgery at 2 months.
Discussion: Subcutis calcinosis is a rare and probably underdiagnosed disease. To our knowledge, only 10 cases have been reported. The pathogenesis is not well-known, tissue damage and calcium disorders are considered as risk factors. The differential diagnoses that can be suspected include calciphylaxis, such as calcifying panniculitis and other local side effects of heparins. Outcome is usually favourable without treatment.
Conclusion: We describe two cases of iatrogenic subcutis calcinosis after injections of calcium-containing heparins, including the second case of poor outcome. Clinicians should be aware of this adverse effect since other heparins such as fondaparinux or low-weight molecular heparins are contraindicated in patients with renal failure, leading to a large prescription of calcium-containing heparins in this population.