Reazioni cutanee avverse da vitamina K: Descrizione di tre casi e revisione della letteratura

Phytomenadione (vitamin K) is essential for liver biosynthesis of prothrombin and clotting factors VII, IX and X. Few cutaneous adverse reactions to vitamin K1 intramuscular administration have been reported in literature and almost all the cases were related to fat-soluble preparations. Two main clinical patterns have been described: a) Eczematous-urticarial pruritic plaques of each onset at the site(s) of injection or generalized, even after a single dose of vitamin K1 administration. These usually disappear in few weeks (2-4), leaving no signs, b) Erythematous-pigmented sclerodermatous plaques of late onset, that usually come out after high doses of vitamin K1 and take months or years to disappear, leaving pigmented and/or atrophic areas. Vitamin K1 is more commonly employed to treat hypothrombine- mic conditions resulting from chronic liver disease. This is the reason why, at first vitamin K1 adverse reactions were described only in patients with liver disease (alcoholic cirrhosis or chronic active hepatitis), while, subsequently), these reactions have also been reported in patients without liver compromission. Local vitamin K1 hypersensitivity probably has an immunological basis (type IV or cell-mediated immune response) that can be tested with patch and/or prick test. These tests often give rise to positive results for pure vitamin K1 or its oleous preparation, while they almost always yield negative results for individual components of vehicles or water soluble preparation of vitamin K3. We describe three new cases of skin hypersensitivity to vitamin K1 that developed in patients with liver disease, long time treated with fat-soluble vitamin K1: two cases had aczematous- urticarial plaques, only at the injection sites or generalized, the other had a sclerodermatous evolution.