Fragrances

All (consecutive) patients

Baseline series with fragrance screening markers

Patients with history of fragrance intolerance

PT selected own products

PT additional fragrance series from the start

Patients with positive PT reaction to fragrances/fragranced products

PT 2nd round supplementary to above

PT single ingredients (obtained from manufacturer) of positive product; fragrance mixture in creams, etc., often provided as mixture; may need additional breakdown testing

ROAT, if PT reaction is doubtful (equivocal) or to verify and establish current relevance of a positive PT reaction

Outcome

Discuss and evaluate relevance based on labelling information

Counsel patient regarding avoidance (also if mixes were positive without mix breakdown having been tested or remaining negative)¹

¹Conservatively, sensitisation to all ingredients of the mix may be assumed. However, pragmatically, the patient can be advised to make a self-test (similar to ROAT) with a desired product before buying and actually using it.

PT: patch test

12.5 Prevention

Primary prevention means, in this context, the avoidance of new cases of sensitisation to a fragrance substance, that is, healthy persons should not get sensitised. Secondary prevention basically means that persons who already got sensitised avoid future contact to their allergen(s) to prevent relapses of allergic contact dermatitis. Tertiary prevention, which implies limiting the severity of an existing disease by intensive and often continuous or repeated care (also called rehabilitation), has a role in the management of contact allergic patients only in the rare instances where allergen avoidance is not possible. Some components of prevention by different actors are outlined in Table 12.2.

Table 12.2

Different measures of prevention concerning an allergen ‘X’

Measure	Primary prevention	Secondary prevention
Information (labelling)	Consumer: decision not to buy a product containing X	Dermatologist: enable adequate diagnostics
Information (labelling)	Consumer: decision not to buy a product containing X	Patient: avoidance of all products containing X
Formulation/substitution	Producer: deliberate avoidance to use X in products	…Will increase choice of products for patient with contact allergy to X
Restriction of use concentration	Regulator/producer: reduce substantially the likelihood of new sensitisation to X in consumers	…Will possibly allow the use of X in some product categories for weakly sensitised patients
Prohibition	Regulator/producer: eliminate risk of sensitisation to X in consumers	…X will become irrelevant for patients in those products for which ban is effective

Different means, if partly overlapping, are used to achieve above objectives regarding contact allergens in general and fragrance substances in particular. Premarketing screening of newly introduced substances regarding different toxicological endpoints, including contact sensitisation, aims at identifying a hazard at a sufficiently early stage, with the consequence of (1) not marketing the substance, (2) establishing use concentration limits or (3) classifying the substance as ‘safe without restrictions’. This process aiming at induction and primary prevention, respectively, has been formalised by industry in terms of a ‘quantitative risk assessment (QRA)’ [1

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