Suberythrodermic pustular psoriasis induced by clopidogrel

Clopidogrel Hypersensitivity: Pathogenesis, Presentation and Diagnosis

This paper provides an overview of the pathogenesis, presentation and diagnosis of clopidogrel hypersensitivity. The majority of clopidogrel hypersensitivity cases are due to a T cell mediated Gell and Coombs Type IV reaction. History, histology, and patch testing have shown consistency with a T cell mediated mechanism. Clopidogrel reactions most commonly present as a mild delayed maculopapular erythematous rash 5 to 10 days after introduction of the drug, and do not always require discontinuation of the drug. Severe cutaneous, systemic, and immediate adverse reactions to clopidogrel are rare. For the diagnosis of clopidogrel hypersensitivity, drug causality can be determined using patch testing, or for mild reactions, recurrence of symptoms after drug reintroduction, although neither are required for diagnosis.

A joint allergist/cardiologist classification for thienopyridines hypersensitivity reactions based on their symptomatic patterns and its impact on the management strategies

The role and importance of thienopyridines such as ticlopidine, clopidogrel, and prasugrel is well-established for several indications, ranging from prevention of acute coronary syndromes to percutaneous coronary interventions, where the dual antiplatelet therapy represents the gold standard to avoid denovo coronary stenosis. However, there is a significant cohort of patients with coronary artery disease who may manifest hypersensitivity reactions to thienopyridines. The examination of the various case reports from medical literature leads to identify mainly four clinical patterns of hypersensitivity to thienopyridines which involves more frequently cutaneous, hematologic, and articular tissues, therefore the kind and predominance of clinical symptoms may determine a different clinical approach to overcome or neutralize thienopyridines hypersensitivity.

Hypersensitivity reactions to modern antiplatelet and anticoagulant drugs

Anticoagulation and antiplatelet drugs are among the most commonly used medical drugs. In addition to the long-established heparins, hirudins, coumarins and antiplatelet drugs such as acetylsalicylic acid, numerous novel and predominantly synthetic pharmacologic agents have come onto the market in recent years. These new agents act at various sites in coagulation and have significantly broadened treatment options. Whilst immunological hypersensitivity reactions are on the whole rare, they have a considerable impact on patient management when they do occur. The present overview discusses the currently known hypersensitivity reactions to anticoagulant and antiplatelet agents, with particular attention to the newer substance classes including P2Y₁₂ inhibitors, glycoprotein IIb/IIIb receptor antagonists, direct factor Xa inhibitors and direct thrombin inhibitors.

Clopidogrel: a possible exacerbating factor for psoriasis

A 64-year-old man developed palmoplantar pustulosis eventuating into palmoplantar pustular psoriasis following treatment with diltiazem, atenolol, aspirin and atorvastatin for suspected coronary artery disease (CAD). Treatment for psoriasis, stopping atenolol and substituting aspirin with clopidogrel did not benefit. Subsequently, he stopped all his drugs and did not develop psoriasis or symptoms/signs of CAD. Re-challenge with oral clopidogrel precipitated his skin lesions. This case has implications for patients having psoriasis and cardiovascular comorbidity where clopidogrel/ticlopidine or aspirin may not be a useful alternative.