Abstract
BACKGROUND: Vitamin K(1) (phytomenadione) is a fat-soluble naturally occurring vitamin that is widely used to treat certain coagulation disorders. Adverse cutaneous reactions to vitamin K(1) can occur; however, owing to its low incidence and considerable variability in presentation and morphology, its diagnosis can be easily overlooked. Managing these reactions may be challenging for patients and clinicians. Therefore, reviewing the adverse cutaneous reactions to vitamin K(1) is important. CASE SUMMARY: Here we report the case of a 50-year-old woman with no pre-existing hepatic disease who developed a cutaneous allergic reaction to subcutaneous vitamin K(1) that presented as localized eczematous plaques at the vitamin K(1) injection site. The eruption developed within 5 d of the injection and persisted for 32 mo despite treatment with topical and intralesional steroids. Eczema was diagnosed based on the results of the pathological examination, immunohistochemical staining, and a skin biopsy. The patient was advised to take herbal medicines orally twice daily. After treatment and follow-up, the patient's eczematous urticarial plaques improved and her condition stabilized. CONCLUSION: Here we present the first case of a cutaneous allergic reaction to subcutaneous vitamin K(1) that was successfully treated with Chinese medicine.