Contact dermatitis caused by Tinosorb® M: the importance of pach testing with pure methylene bis-benzotriazolyl tetramethylbutylphenol.

Tinosorb® M is a widely used ultraviolet (UV) filter complex provided as an emulsion that contains the UV filter methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT) (45–55%, CAS no. 103597-45-1), decyl glucoside (6–10%), propylene glycol (0.2–0.6%), and xanthan gum (0.1–0.5%). Fewer than 15 cases of contact allergy to Tinosorb® M have been published (1–7), and, to our knowledge, in only one of them (7) has the pure UV filter MBBT been tested, as it was unavailable until 1 January 2014, when Chemotechnique Diagnostics introduced it as a ‘pure’ hapten in their European photopatch Extended (EPE) series.