Dermatitis®

Little is known about the epidemiology of contact dermatitis in production workers (PWs).

The aims of this study were to estimate the prevalence of contact dermatitis and characterize clinically relevant and occupationally related allergens among North American PWs undergoing patch testing.

This was a retrospective cross-sectional analysis of North American Contact Dermatitis Group data from 1998 to 2014.

Of 39,332 patch-tested patients, 2732 (7.0%) were PWs. Among PWs, most were men (62.4%) and white (83.9%). A history of childhood eczema was uncommon (11.3%). Prevalent occupations included machine operators (27.3%); fabricators, assemblers, and hand-working occupations (16.8%); and precision metalworking occupations (16.1%). The most frequent sites of dermatitis were the hands (53.8%) and arms (29.4%), which were significantly more commonly affected compared with non-PWs (P < 0.0001). Occupationally related skin disease, allergic contact dermatitis, and irritant contact dermatitis were also significantly more common in PWs (49.9% vs 10.6%, 58.9% vs 53.7%, and 32.7% vs 25.7%, respectively; all Ps < 0.0001). Epoxy (15.3%), thiuram mix (8.3%), carba mix (8.1%), formaldehyde (6.3%), and cobalt (5.9%) were the most frequent occupationally related allergens. The top allergen sources included adhesives/glues (16.0%), metalworking fluids/cutting oils (6.8%), and coatings (6.3%).

Production workers had a high rate of occupationally related skin disease, as well as irritant and allergic contact dermatitis. Involvement of exposed body areas was common. Frequently identified allergens included adhesives/glues, rubber accelerators, metals, and preservatives.

Little is known about the epidemiology of contact dermatitis (CD) in print machine operators (PMOs).

The aims of this study were to estimate the prevalence of CD and characterize clinically relevant and occupationally related allergens among PMOs undergoing patch testing.

This was a retrospective cross-sectional analysis of the North American Contact Dermatitis Group data from 1998 to 2014.

Of 39,332 patch-tested patients, 132 (0.3%) were PMOs. Among PMOs, most were male (75.0%) and white (92.4%). The majority were printing press operators (85.6%). The most frequent sites of dermatitis were hands (63.6%), arms (29.5%), and face/scalp (24.2%). More than half had an occupationally related skin condition (56.1%). Final diagnoses were most commonly allergic CD (58.3%) and irritant CD (33.3%). Cobalt (20.8%), carba mix (12.5%), thiuram mix (8.3%), and formaldehyde (8.3%) were the most frequent occupationally related allergens. The top allergen sources included inks (22.9%), gloves (20.8%), and coatings/dye/copy/photographic chemicals (14.6%).

Allergic CD, irritant CD, and involvement of exposed body areas were common among PMOs. Common allergens included rubber accelerators, metals, and preservatives.

Preservative sensitivity patterns evolve with changing use patterns in products. During the last decade, the use of methylisothiazolinone (MI) at higher concentrations in both leave-on and rinse-off products has significantly increased. This is the first North American Contact Dermatitis Group reporting cycle that includes both methylchloroisothiazolinone (MCI)/MI and MI data.

The aim of this study was to report the prevalence of isothiazolinone allergy (MCI/MI and MI) in the North American Contact Dermatitis Group patch-test population from January 1, 2013, to December 31, 2014.

At 13 centers in North America, 4860 patients were patch tested in a standardized manner with a series of 70 allergens, including MCI/MI 0.01% aqueous (aq) and MI 0.2% aq.

Three hundred five patients (6.3%) had a positive reaction to MCI/MI; this is a significant increase from the previous cycle (5.0%, 2011–2012; P = 0.011). Five hundred twenty-one patients (10.7%) had a positive reaction to MI. These 2 isothiazolinones were among the most common preservative allergens in the 2013 to 2014 cycle; 11.9% of patch-tested individuals were allergic to 1 or both isothiazolinones. Individuals with MCI/MI and MI allergy were significantly more likely to have occupationally related skin disease (P < 0.0001) and hand dermatitis (P < 0.0001, P = 0.0474).

The epidemic of isothiazolinone sensitivity documented in Europe is now in North America. Patch testing with only MCI/MI 0.01% aq will miss approximately half of isothiazolinone allergy cases, whereas testing with only MI 0.2% aq will miss approximately 10% of isothiazolinone allergy cases.

The preservatives methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and MI are well-known contact sensitizers. Recently, an increase in the contact allergy frequency for MI 0.2% aqueous (aq) has been seen in many European countries paralleled with an increase in MCI/MI allergy. Many of the MI-allergic patients do not react to MCI/MI 0.01% or 0.02% because the concentration of MI in these preparations is too low (25 and 50 ppm, respectively) to elicit a positive patch test reaction.

The aims of this study were to investigate the prevalence of contact allergy to MI in the participating clinics representing various countries all over the world, to assess how many additional individuals with contact allergy are found by testing MI 0.2% aq in parallel with MCI/MI 0.02%, and to assess the clinical relevance of MI and MCI/MI allergies.

In 9 dermatology clinics representing 9 countries, 3865 consecutive patients with dermatitis were patch tested with MI 0.2% aq and in parallel with MCI/MI 0.02% aq, provisionally included into the baseline series. An assessment of clinical relevance in those allergic to MI was also made.

Contact allergy to MI was found in 284 patients (7.3%). The frequency of contact allergy varied from 0.8% to 10.9% in different centers. Simultaneous reactivity to 200 ppm of MCI/MI was found in 67.3% of the MI-positive patients. Contact allergy to MI alone without any simultaneous contact allergy to 200 ppm of MCI/MI was diagnosed in 93 patients (32.7%; 2.4% of all tested patients). The contact allergy to MI and/or MCI/MI could explain or contribute to dermatitis in more than 60% of the MI-allergic patients.

Methylisothiazolinone of 2000 ppm needs to be patch tested on its own to not miss contact allergy.

The preservative methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) is a well-known contact sensitizer. Historically, there have been different opinions on the optimal patch test concentration of MCI/MI, and both 0.01% and 0.02% aqueous (aq.) have been proposed. In 2011, based on literature reviews, it was recommended that the concentration of 0.02% aq. should be used in the international baseline series.

The aim of this study was to verify the recommendation from 2011 by comparing the patch test results from consecutive patch testing with MCI/MI 0.01% and 0.02% in clinics representing countries around the world.

Two thousand seven hundred three consecutive patients with dermatitis in 8 dermatology clinics representing 8 countries were patch tested with MCI/MI 0.01% aq. and, in parallel with MCI/MI 0.02% aq., provisionally included in the baseline series.

Contact allergy to MCI/MI at 0.01% and 0.02% was found in 3.7% and 5.6% of the patients, respectively (P < 0.001).

Methylchloroisothiazolinone/MI 0.02% aq. (dose, 6 μg/cm²) diagnoses significantly more contact allergy than 0.01% (dose, 3 μg/cm²), without resulting in more adverse reactions. Methylchloroisothiazolinone/MI at 0.02% aq. should therefore be continuously used in the international baseline series.