Hydroquinone

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Overview based on studies according to accepted standard conditions with a standard test concentration of 1% HQ in petrolatum, evaluation of test results according to ICDRG criteria for scoring sensitisation reactions; irritant reactions specified in part of the studies; data acceptable as key study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Occupational dermatoses at a film laboratory. Follow-up after modernization.

Author:

Liden C

Year:

1989

Bibliographic source:

Contact Dermatitis 20, 191 - 200

Reference 2

Reference Type:

publication

Title:

Analysis of patients with allergic patch test reactions to plastics and glues series.

Author:

Tarvainen K

Year:

1995

Bibliographic source:

Contact Dermatitis 32, 346 - 351

Reference 3

Reference Type:

publication

Title:

Allergic and irritant patch test reactions to plastic and glue allergens. (Short communication)

Author:

Kanerva L, Jolanki R, Estlander T

Year:

1997

Bibliographic source:

Contact Dermatitis 37, 301 - 302

Reference 4

Reference Type:

publication

Title:

Patch-test reactions to plastic and glue allergens.

Author:

Kanerva L, Jolanki R, Alanko K, Estlander T

Year:

1999

Bibliographic source:

Acta Derm Venereol 79, 296 - 300

Reference 5

Reference Type:

publication

Title:

Occupational skin and respiratory diseases among hairdressers.

Author:

Leino T, Tammilehto L, Hytönen M, Sala E, Paakkulainen H, Kanerva L

Year:

1998

Bibliographic source:

Scand J Work Environ Health 24, 398 - 406

Materials and methods

Type of sensitisation studied:

skin

Study type:

survey

Principles of method if other than guideline:

Patch tests performed according to standard conditions and ICDRG criteria

Test material

Test material information

Constituent 1

Reference substance name:

Hydroquinone

EC Number:

204-617-8

EC Name:

Hydroquinone

Cas Number:

123-31-9

Molecular formula:

C6H6O2

IUPAC Name:

hydroquinone

Method

Type of population:

other: general and occupational

Ethical approval:

not applicable

Subjects:

see Table

Clinical history:

see Table

Details on study design:

TYPE OF TEST(S) USED: patch test (epicutaneous test)

ADMINISTRATION
- Type of application: occlusive
- Description of patch: mostly Finn chambers
- Vehicle / solvent: petrolatum
- Concentrations: 1%
- Volume applied: no data
- Testing/scoring schedule: 48 h patch, readings at 48, 72 h, and 4-6 d (for exceptions see Table)
- Removal of test substance: 48 h

EXAMINATIONS
- Grading/Scoring system: ICDRG

Results and discussion

Results of examinations:

There was no indication of sensitisation to HQ in patch tests with patients from dermatology clinics or hairdressers with work-related skin and respiratory symptoms. In contrast, a sensitisation rate of 6.2% was found in employees at a film laboratory (number with actual exposure to HQ not known).
The vehicle was found to influence the outcome of findings. Whereas no skin reaction was observed with 1% HQ in petrolatum, 1% HQ in water provoked erythema (irritant reaction) and staining possibly due to instability of HQ in aqueous solution.

Any other information on results incl. tables

Table: Overview on patch test studies with 1% HQ (w/w in petrolatum, evaluation according to ICDRG criteria)

Study period	Study subjects	Test condition	Readings (after start of exposure)	Allergic reactions	Irritant reactions	Remarks	Reference
1983-1986	65 persons working at the Swedish Television Film Laboratory^b	48 h occlusive patch (Finn chamber)	72 h, 2 w	4/65 (6.2%)	Of the 65 persons, 10 were diagnosed with occupational dermatoses. A single person with occupational hand eczema showed a positive reaction to HQ besides reactions to other chemicals		Liden 1989
	10 test persons with occupational dermatoses working at the Swedish Television Film Laboratory			1/10
	Control group of unexposed healthy volunteers	1% HQ in pet. 48 h occlusive patch (Finn chamber or Al-test)	72 h		0/11 individuals with erythema or staining	Use of petrolatum as vehicle prevents irritant reactions and staining
		1% HQ in water 48 h occlusive patch (Finn chamber or Al-test)	72 h		Finn chamber: 2/11 Al-test: 6/11 individuals with erythema or staining
1985-1992	343 patients of Finnish dermatology clinic	24 or 48 h occlusive patch (Finn chamber)	24, 48, 72 h or 48, 72, 96 h	0/343	No data		Tarvainen et al. 1995
3 years	173 patients of Finnish dermatology clinic	48 h occlusive patch	48, 72 h, 4-6 d	0/173	11/173 (6.4%)^a		Kanerva et al. 1997
1991-1996	357 patients of Finnish dermatology clinic	48 h occlusive patch	48, 72 h, 4-6 d	0/357	11/357 (3.1%)		Kanerva et al. 1999
1994	54 Finnish hairdressers with work-related skin and respiratory symptoms	48 h occlusive patch (Finn chamber)	48, 72 h, 4-6d	0/54	No data		Leino et al. 1998

^a presumably included in the test population of Kanerva et al. 1999

^b the test population included persons with and without chemical exposure, number of subjects with exposure to HQ is not known

Applicant's summary and conclusion

Conclusions:

There was no indication of sensitisation to HQ in patch tests with patients from dermatology clinics or hairdressers with work-related skin and respiratory symptoms. In contrast, a sensitisation rate of 6.2% was found in employees at a film laboratory (number with actual exposure to HQ not known).
The vehicle was found to influence the outcome of findings. Whereas no skin reaction was observed with 1% HQ in petrolatum, 1% HQ in water provoked erythema (irritant reaction) and staining possibly due to instability of HQ in aqueous solution.

Executive summary:

Several publications report on patch tests performed according to standardized conditions, generally with 48 h application via Finn chambers and reading according to ICDRG criteria after 48 and 72 h, and 4 to 6 days. Patch test data were reported for several groups of patients of Finnish dermatology clinics (populations partly overlapping covering a total study period of 1985 to 1996: Tarvainen et al. 1995; Kanerva et al. 1997, 1999), a group of 54 Finnish hairdressers with work-related skin and respiratory symptoms (Leino et al. 1998), and 65 persons working at the Swedish Television Film Laboratory (Liden 1989).

The individual results are summarised above in the section "Any other information on results incl. tables".

There was no indication of sensitisation to HQ in patch tests with patients from dermatology clinics or hairdressers with work-related skin and respiratory symptoms. From 65 persons working at a film laboratory (number with exposure to HQ not known), 4 (6.2%) showed a positive patch test reaction to 1% HQ. The vehicle was found to influence the outcome of findings. Whereas no skin reaction was observed with 1% HQ in petrolatum, 1% HQ in water provoked erythema (irritant reaction) and staining possibly due to instability of HQ in aqueous solution.