Delayed Vesicular Urticarial Dermatosis Due to Apixaban

Area of Science:

• Pharmacology
• Dermatology
• Immunology

Background:

• Novel oral anticoagulants (NOACs), particularly Factor Xa inhibitors like apixaban, are widely prescribed for thrombosis and atrial fibrillation.
• Cutaneous adverse drug reactions (cADR) are T-cell mediated delayed hypersensitivity responses.
• Evaluating cADR to NOACs presents diagnostic challenges due to a lack of standardized protocols.

Observation:

• A 78-year-old female developed a vesicular-urticated erythematous rash approximately nine days after initiating apixaban for stroke prophylaxis.
• The rash initially appeared on her upper extremity and spread to her face.
• Symptoms improved with hydroxyzine and prednisone, and the patient was switched to warfarin.

Findings:

• Patch testing with apixaban, rivaroxaban, and edoxaban yielded negative results.
• The Naranjo scale indicated a probable drug reaction (score 5-6).
• This case represents the first reported instance of a non-severe cADR to apixaban.

Implications:

• Patch testing, alongside careful clinical evaluation and consideration of alternative anticoagulants, is valuable for diagnosing cADR to Factor Xa inhibitors.
• Further research is needed to establish standardized diagnostic approaches for NOAC-induced cutaneous reactions.
• Prompt recognition and management of cADR are crucial for patient safety and adherence to anticoagulation therapy.