Identity and formulation

p-Phenylenediamine has CAS number 106-50-3. INRS lists dye manufacture and ingredients in hair-colouring products among its applications. Derivatives and salts should not automatically be treated as identical. Establish ingredients and the specific formulation. A trade description such as gentle or professional dye does not prove absence of PPD or establish that a replacement ingredient has no capacity to sensitise skin.

Allergy differs from irritation

PPD can cause sensitisation and allergic contact dermatitis. Irritation from other ingredients or wet work may coexist, but the mechanism differs. A hand lesion does not identify the responsible agent by itself. Occupational dermatitis needs task history and clinical evaluation; home-made tests applying product to a worker’s skin are not an appropriate way to establish diagnosis or fitness for continued exposure.

Overlooked contacts

Assess preparation, application, rinsing, cleaning and handling of contaminated tools. In industrial manufacture, include dust and surfaces during charging or packaging. Contact is not restricted to opening the product: a handle, lid or glove exterior can transfer it later. Observe the complete sequence with the people who normally perform it, including interruptions and the transition back to clean tasks or equipment.

Reduce contact through work organisation

Arrange tasks and utensils to avoid touching product or contaminated surfaces, separating clean and used materials. Select gloves for the formulation and task duration using reliable supplier information. A glove being present does not establish sufficient protection. Removal, replacement and cleaning should prevent protective equipment becoming a contact source itself, especially when workers move between preparation, application and cleaning during the same session.

Consider other exposure routes

Dispersed solid material can create relevant inhalation exposure; ILO/WHO also describes asthmatic reactions. This does not mean every use of a formulated product produces the same respiratory exposure. Distinguish solid substance, mixture and operation. Assessment should determine which routes need investigation and which controls are required, without automatically transferring a manufacturing scenario to a hairdressing salon using a different formulation.

Follow-up and substitution

Report compatible symptoms early so exposure and professional care can be assessed. Changing brands while retaining the same ingredient may not resolve the problem. An alternative requires review of composition, hazards and use. Where sensitisation is confirmed, professionals should individualise work-adaptation decisions. Retain product information and task chronology so clinical and preventive assessments have concrete evidence rather than only a general description of working with dyes.