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

Area of Science:

• Allergy and Immunology
• Dermatology
• Toxicology

Background:

• Titanium (Ti) is a metal with a unique exposure profile, often overlooked as an allergen.
• Evaluation of titanium sensitization is crucial in specific clinical contexts due to increasing exposure.
• Understanding titanium's role in allergic reactions is essential for accurate diagnosis and management.

Purpose of the Study:

• To characterize the clinical features of patients experiencing titanium sensitization.
• To identify common exposure sources and clinical presentations associated with titanium allergy.
• To assess the diagnostic utility of metal series patch testing in suspected titanium sensitivity.

Main Methods:

• Retrospective cohort analysis of 255 patients patch tested with a metal series.
• Inclusion of patients tested between 2012 and 2024 at a tertiary contact dermatitis clinic.
• Evaluation of clinical characteristics and sensitization patterns, including titanium oxalate reactions.

Main Results:

• Positive titanium oxalate reactions occurred in 5% of cases, frequently linked to jewelry (38%).
• Dermatitis from titanium typically presented adjacent to the contact site, primarily on hands and fingers.
• Significant percentages of patients with tattoo-induced dermatitis (100%) and post-orthopaedic implant reactions (67%) would have been missed without the metal series.
• Two cases associated with medical implants developed generalized rash, one with Bullous pemphigoid (BP).

Conclusions:

• Titanium sensitization may become more prevalent due to medical devices, implants, and recreational exposures like 'nickel-free' jewelry and tattoos.
• Titanium-induced Bullous pemphigoid (BP) is a notable phenomenon requiring further investigation at the intersection of allergology and immunology.
• Metal series patch testing is vital for diagnosing allergies to less common metals like titanium, especially in cases involving implants and tattoos.