Recommendation to increase the test concentration of methylchloroisothiazolinone/methylisothiazolinone in the European baseline patch test series - on behalf of the European Society of Contact Dermatitis and the European Environmental and Contact Dermatitis Research Group.
BACKGROUND
Methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) in aqua is present in the European baseline patch test series at 100 ppm, whereas 200 ppm has been used in Sweden since 1986, in Spain in the late 1980s, and, in recent years, also in the United Kingdom and Ireland.


OBJECTIVE
With regard to MCI/MI, to investigate the data on contact allergy rates in dermatitis patients, the frequencies of allergic contact dermatitis in the same group, and adverse reactions, particularly patch test sensitization in tested dermatitis patients, and to find the optimal patch test concentration as dose in mg/cm(2) .


METHODS
We performed a survey of the literature found via the National Library of Medicine (PubMed, http://www.ncbi.nlm.nih.gov/pubmed, last accessed 20 February 2014).


RESULTS
MCI/MI at 200 ppm aq. diagnosis substantially more contact allergy and allergic contact dermatitis, without any registered increase in patch test sensitization, than the presently used concentration of 100 ppm.


CONCLUSIONS
MCI/MI at 200 ppm aq. is recommended to be included in the European baseline patch test series. To avoid patch test sensitization, a dose of 0.006 mg/cm(2) must not be exceeded, which means a volume of 15 µl for Finn Chambers(®) (Ø 8 mm).
Department of Occupational and Environmental Dermatology, Skåne University Hospital, Lund University, SE 205 02 Malmö, Sweden.
Magnus
M
Bruze
An
A
Goossens
Marléne
M
Isaksson
D000485:Allergens / Q000008:administration & dosage*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D010328:Patch Tests / Q000379:methods*; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects; D013844:Thiazoles / Q000008:administration & dosage*
D000485:Allergens; D011310:Preservatives, Pharmaceutical; D013844:Thiazoles; C011506:2-methyl-4-isothiazolin-3-one; C011421:5-chloro-2-methyl-4-isothiazolin-3-one
CAS no. 55965-84-9; Kathon™ CG; MCI/MI; adverse reactions; allergic contact dermatitis; contact allergy; dose in mg/cm2; micropipette; patch test sensitization; preservative