Titanium: An Unusual Allergen With Various Presentations—A Retrospective Cohort Study

While nickel, cobalt and chrome are considered common allergens, we hypothesise that sensitisation to other metals, including titanium, will become more prevalent in the following years through exposure via medical devices and implants as well as recreationally via 'nickel free' jewellery and tattoos. Titanium-induced BP is an intriguing phenomenon that should be further investigated, on the verge between allergology and immunology.