Vitamin D has many benefits for body and human health. Vitamin D is
involved in calcium homeostasis and bone metabolism, and it can be obtained from
food, but it is produced by the human body too. Vitamin D from foodstuffs is available
in two forms; vitamin D2 [ergocalciferol,] is contained in plants, and vitamin D3
[cholecalciferol] is contained in animals. Furthermore, the vitamin D produced by
human body, is synthesized mainly in the skin. The synthesis of vitamin D in the skin
starts with the conversion of 7-dehydrocholesterol [provitamin D3] to previtamin D by
UVB. Some of the formed vitamin D3 in the skin is transported to the liver and
metabolized to become 25(OH)D3 (calcidiol), then furtherly converted in two steps to
1,25(OH)2D3 (calcitriol), i.e., the biologically active form of vitamin D. Being produced
by the organism, vitamin D shows a high tolerability; thus hypersensitivity reactions to
vitamin D are rarely reported in the literature. From vitamin D, many analogs have
been used successfully to treat secondary hyperparathyroidism or other derivatives
synthetically produced like calcipotriol, calcitriol and maxcalcitol that are used in
dermatologic field as topical therapeutic agents for psoriasis. For this last class of
compounds, given the external use on the skin, cases of allergic contact dermatitis are
described.
Keywords: Allergic Contact Dermatitis, Anaphylaxis, Calcipotrion, Calcitriol,
Cholecalciferol, Delayed-type Reaction, Desensitization, Ergocalciferol,
Immediate-type Reaction, Pro-vitamin D, Vitamin D, Vitamin D3, Vitamin D
Analogs.
