Table 1 Group allocation scheme for certainty of specific occupational causation* among n = 147 hairdressers

Airway disease verified

Yes

Yes

Yes

Yes

No

 I. Obstructive ventilation disease confirmed

n = 5

n = 1

n = 5

n = 23

–

 II. Work-related rhinoconjunctivitis

n = 9

n = 3

n = 7

n = 19

–

 III. both

n = 10

n = 7

n = 13

n = 24

–

Immediate-type-like hypersensitivity reaction to AP or hair dyes

Confirmed

Likely, but not unequivocally confirmed

Unlikely

No

No

 IV. “Positive” reaction to AP or blonde dye in skin (prick) testing

n = 21 with CR^a

n = 1 CR unsure^a

n = 1 CR unlikely^a

–

–

 V. “Questionable” reaction to AP or blonde dye in skin (prick) testing

n = 1 with CR^a (positive SIC)

n = 4^b

n = 3 CR unlikely^a (1x neg. SIC)

n = 3 without CR^a(2x neg. SIC)

n = 1 without CR^a (neg. SIC)

 VI. “Negative” skin prick test to AP/blonde dye

–

n = 2^{b, c}

n = 14^d

n = 63^e

n = 20

 VII. Rating of skin testing for immediate-type-like reactions to AP / blonde dye: “not appraisable”

n = 2 but positive SIC

n = 3^b

n = 6^d

–

–

 VIII. No skin prick test to AP/blonde dye conducted

–

n = 1^b

n = 1

–

–