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Sensitisation data (human)

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sensitisation data (humans)
Type of information:
other: human data
Adequacy of study:
supporting study
other: not rated acc. to Klimisch
Rationale for reliability incl. deficiencies:
other: Any kind of reliability rating is not considered to be applicable, since human studies/reports are not conducted/reported according to standardised guidelines.

Data source

Reference Type:
Epidemiology of contact dermatitis in Spain. Results of the Spanish surveillance system on contact allergies for the year 2008
Gracia-Gavin, J. et al.
Bibliographic source:
Actas Dermosifiliogr. 102 (2): 98 - 105.

Materials and methods

Type of sensitisation studied:
Study type:
study with volunteers
Test guideline
no guideline followed
Principles of method if other than guideline:
A retrospective observational study was carried out in the 5 hospitals of the Spanish Surveillance System on Contact Allergies. All patients underwent skin patch tests with the Spanish standard series. The frequencies of sensitization were normalized for age and gender. One of allergens tested was cobalt chloride as a 1% concentration in petroleum jelly.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Cobalt dichloride
EC Number:
EC Name:
Cobalt dichloride
Cas Number:
Molecular formula:
cobalt(2+) dichloride
Test material form:
not specified
Details on test material:
- Name of test material (as cited in study report): cobalt chloride


Type of population:
Ethical approval:
not specified
- Number of subjects exposed: 1161 patients from 5 Spanish skin allergy units
- Sex: 740 (63.7%) women and 421 (36.3%) men (ratio men to women: 1.76)
- Age: mean age 44.5 years (range, 1-91 years); 65.46% of the patients were over 40 years
- Demographic information: 14.61% of the cases had occupational relevance. Most common occupation was domestic worker/home maker (16.04%), 34.21% of the patients worked in a humid environment, and 10.4% had atopic disease
Clinical history:
The clinical approach was similar in all centers: a full medical history was taken and a general physical examination was performed.
no data
Route of administration:
Details on study design:
TYPE OF TEST(S) USED: patch test (epicutaneous test)

Patch testing was undertaken according to the guidelines of the International Contact Dermatitis Research Group (ICDRG). All patients were studied with the Spanish standard series of the GEIDAC. Cobalt chloride as 1% concentration in petroleum jelly was used as one of the tested allergens.
Finn chambers, True Test and Curatest were used as chambers during testing. Patch testing was conducted by using occlusion for 2 days with Micropore hypoallergenic tape and/or Mefix.

- Grading/Scoring system: readings of the site were conducted on Day 2 and day 4/day 5. All centers took late readings on day 7 if needed. The reactions were assessed using the international scale, where + indicates light nonvesicular erythema, ++ notable papule formation with discrete vesicles, and +++ strong vesiculation and blistering (Uter et al., 2003)*. Only reactions occurring within 96 hours of patch application were considered as positive.
- Statistical analysis: for statistical analysis of the data, the SAS software package (version 9.1, SAS Institute, Cary, NC, USA) and the SPSS software package version 8.0 for Macintosh were used.
The statistical analysis was performed according to international recommendations for presentation and analysis of contact allergy data (Uter et al. 2004)*. Descriptive statistics were calculated for the main sociodemographic and clinical variables, with focus on the so-called MOAHLFA index as the reference instrument for comparison between centers. The definition of atopy included only personal history of atopic dermatitis (Uter et al. 2004)*. Possible differences due to use of allergens from different suppliers were ignored (ESSCA, 2004)*. In the study of allergen sensitization rates, direct sex and age adjustment was performed (Schnuch, 1996)*, using the ESSCA reference population (65% women, 35% men; 50%<40 years, 50%>40 years)(ESSCA, 2004)*. For the proportions obtained, 95% confidence intervals (CI) were also calculated. The significance of the results was assessed using the χ2 test, comparing the proportion of patients with a positive reaction and those with a negative reaction. The χ2 test and the Fisher exact test were used for comparing mixes with the primary allergen of the mix.

- Uter W, Arnold R, Wilkinson J, Shaw S, Perrenoud D, Rili C, et al. A multilingual European patch test software concept: Winalldat/ESSCA. Contact Dermatitis. 2003; 49:270-1.
- Uter W, Schnuch A, Gefeller O, ESCD working group: European Surveillance System on Contact Allergies. Guidelines for the descriptive presentation and statistical analysis of contact allergy data. Contact Dermatitis. 2004;51:47-56.
- ESSCA Writing Group. The European surveillance system of contact allergies (ESSCA): Results of patch testing the standard series, 2004. J Eur Acad Dermatol Venereol. 2008; 22: 174-81.
- Schnuch A. PAFS: Population-adjusted frequency of sensitization. (I) influence of sex and age. Contact Dermatitis. 1996;34:377-82.

Results and discussion

Results of examinations:
- 60 patients (5.17%) of 1161 patients tested reacted positive to cobalt chloride
- sex-and age-adjusted percentage was 5.10% (95% Cl: 3.79% - 6.42%)
- cobalt chloride sensitization was slightly more frequent in women (5.87% vs 3.68%, although the difference was not statistically significant.

Applicant's summary and conclusion

60 patients (5.17%) of 1161 patients tested reacted positive to cobalt chloride with sex-and age-adjusted percentage of 5.10% (95% Cl: 3.79% - 6.42%)
Cobalt chloride sensitization was slightly more frequent in women (5.87% vs 3.68%, although the difference was not statistically significant.