Positive Patch Test Reactions to Carba Mix and Thiuram Mix: The North American Contact Dermatitis Group Experience (1994–2016)

Abstract

Background/ObjectiveThis study characterizes concomitant reactions to carba mix (CM) and thiuram mix (TM) in a large North American population. Because thiurams and dithiocarbamates have structural similarity, concomitant reactions are expected.MethodsThe 1994–2016 North American Contact Dermatitis Group data were analyzed. Patients with a final reaction interpreted as “allergic” to either CM or TM were included.ResultsA total of 49,758 patients were tested to both CM and TM. A total of 3437 (6.9%) had positive reactions to CM and/or TM including the following groups: CM+ only (n = 1403, 40.8%), TM+ only (n = 1068, 31.0%), or both (n = 966, 28.1%). A total of 47.5% of TM+ patients were positive to CM and 40.8% of CM+ patients were positive to TM. Male sex, occupationally related dermatitis, and hand involvement were significantly more common in individuals positive to CM and/or TM as compared with those who were negative (P < 0.0001). More than 80% of CM+/TM+ reactions were currently relevant. Gloves were the most common source of CM and TM; clothing and footwear were also frequent.ConclusionsCarba mix and TM remain important, clinically relevant allergens. Although significant concomitant reaction frequency was demonstrated, more than half of the patients reacting to either CM or TM would have been missed if both had not been tested, underscoring the importance of testing to both.

Occupational Contact Dermatitis in Dental Personnel: A Retrospective Analysis of the North American Contact Dermatitis Group Data, 2001 to 2018

“…30 The rubber accelerators in thiuram mix and carba mix are important occupational allergens in latex and nonlatex medical gloves. 31 Here, 16.1% of dental personnel had occupationally related reactions to thiuram mix and 14.1% to carba mix. Among 799 dental nurses surveyed in Finland, rubber chemicals (thiuram mix) were one of the most frequent causes of ACD, seen in 11.6% of dental nurses.…”

Occupational contact allergy: The European perspective–Analysis of patch test data from ESSCA between 2011 and 2020

“…However, these results must be interpreted with caution because carba mix contains not only carbamates but 1,3-DPG, a problematic test substance frequently causing false-positive irritant reactions, which may explain the high positivity rate. 32,[37][38][39] Therefore, the clinical relevance of carba mix sensitizations should be proven by testing the components of the carba mix, especially 1,3-DPG and by testing the thiuram mix or its components as well as patient's own material. A false positive reaction to carba mix has major consequences for the patient's occupational opportunities, because the selection of protective gloves is severely compromised when carbamates must be avoided.…”

Occupational Hand Dermatitis

“…Such studies in North American populations were lacking. A recent analysis filled this gap and found over 40% of individuals with positivity to one allergen were positive to the other [ 24 ]. The researchers went on to find that carba mix and thiuram mix allergies were commonly associated with occupation and, in particular, with exposure to personal protective equipment such as gloves, which is consistent with prior literature [ 22 ].…”