Patch Testing with Formaldehyde 2.0% in Parallel with 1.0% by the Swedish Contact Dermatitis Research Group

Abstract

In a multicentre study consecutively patch-tested dermatitis patients were tested simultaneously with 1.0% and 2.0% (w/v) formaldehyde in aqua applied with a micropipette (15 µl) to the filter paper disc in Finn Chambers (0.30 mg/cm(2) and 0.60 mg/cm(2), respectively). A total of 2,122 dermatitis patients were patch-tested. In all, 77 (3.6%) patients reacted positively to formaldehyde; 37 reacted only to 2.0%, 35 reacted to both concentrations and 5 patients reacted only to 1.0%. Significantly more patients were thus diagnosed with contact allergy to formaldehyde with 2.0% compared to 1.0% (p < 0.001) without causing more irritant reactions. The detected number of isolated allergic reactions to the 2 formaldehyde-releasers in the Swedish baseline series and not to formaldehyde itself raises the question whether quaternium-15 1.0% and diazolidinyl urea 2.0% should be present in the Swedish baseline series.

Thoughts on how to improve the quality of multicentre patch test studies

“…There are thus different types of MPTS in which at least two patch test clinics participate. One type involves collecting retrospective data , another type is represented by networks producing patch test data constantly , and a third type is the prospective MPTS on, for example, the concentration (dose/cm 2 ) of a certain sensitizer to be used .…”

Skincare products containing low concentrations of formaldehyde detected by the chromotropic acid method cannot be safely used in formaldehyde-allergic patients

“…Patch test reactions to dilution series of formaldehyde, dimethyloldimethylhydantoin (DMDMh), dimethylhydantoin (DMh) and repeated open application test (ROAT) moisturizers containing high (H), medium (M) and low (L) levels of formaldehyde and control (0) moisturizer in individuals with(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) and without(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27) hypersensitivity to formaldehyde, as well reactions to the various aqua; pet, petrolatum. aThe strongest recorded reaction on day 4 or day 8 is given.…”

“…At our department we have for decades used formaldehyde 2·0% (0·60 mg cm −2 ) in case of doubtful reactions to formaldehyde 1·0%, which has been the recommended patch test concentration in the European baseline patch test series . However, based on the results of recent studies, the European Society of Contact Dermatitis has recommended that the formaldehyde concentration should be increased to 2·0% (0·60 mg cm −2 ) in the European baseline series …”

Formaldehyde in cosmetics in patch tested dermatitis patients with and without contact allergy to formaldehyde

“…The recommended patch test concentration (1.0%) has been discussed, owing to false‐positive and false‐negative reactions . However, on the basis of the results of recent studies and recommendations by the European Society of Contact Dermatitis, the formaldehyde concentration has been increased to 2.0% (0.60 mg/cm 2 ) . The new information on formaldehyde contributed to formaldehyde being the American Contact Dermatitis Society ‘Contact Allergen of the Year’ for 2015 .…”