Evaluating work relatedness
Occupational contact dermatitis (OCD) is a multifactorial disease, often a combination of allergic, irritant and endogenous factors.
Occupation may be relevant especially when dermatitis symptoms flare with work and improve when away from work. In order to asses work-relatedness is important to take a full occupational exposure history and accurately identify allergens or irritants in the material safety data sheets. A significant step in the management of OCD is determining causality.
Criteria for diagnosing occupational contact dermatitis have been established by Mathias1 seen in the table below. 4 of the 7 criteria should be met to make a diagnosis of occupational dermatitis.
| 1 | Is the clinical appearance consistent with contact dermatitis? |
| 2 | Are there workplace exposures to potential cutaneous irritants or allergens? |
| 3 | Is the anatomic distribution of dermatitis consistent with the form of cutaneous exposure in relation to the job task? |
| 4 | Is the temporal relationship between exposure and onset consistent with contact dermatitis? |
| 5 | Are non-occupational exposures excluded as likely causes? |
| 6 | Does avoiding exposure lead to improvement of the dermatitis? |
| 7 | Do patch tests or provocation tests implicate a specific workplace exposure? |
A detailed exposure history is essential (this is briefly touched on in Module 4 Making a diagnosis) and includes
- Employer
- Industrial sector
- Description of work site
- Number of employees/ co-workers with similar issues
- Health and Safety Department
- Education prior to starting work
- Employee
- Modified work available / instituted
- Job role and description of tasks
- Work schedule
- Multiple jobs + Description
- Exposures
- Work place materials (+ Material Safety Data Sheets)
- PPE + use of PPE by employee
- Hobbies/Housework outside the workplace
- Hand hygiene practices
- Wet work
- Skin problem
- Past medical history/ Atopy/ Other skin diseases
- Duration of rash
- Variation of symptoms during the day/ days off/ holidays
- Days off from skin problem
- Treatment – OTC moisturisers/ barrier creams + Prescribed treatments
- Worker’s compensation claims
Material Safety Data Sheets (MSDS)
- Otherwise known as safety data sheets
- Describe the properties of a substance and provide information on the safe use and handling of materials
Format of a MSDS2
The minimal requirements for an MSDS must include information regarding:
- both chemical and common (trade) names of all hazardous ingredients
- physical and chemical characteristics of the agent or agents
- physical hazards, such as flammability or explosive reactivity
- medical symptoms, signs, or known diseases that can be caused or aggravated by exposure
- primary route or routes of entry
- legal time-weighted exposure limits and toxicity information established by OSH
- carcinogenicity
- precautions for safe handling and use, including appropriate hygienic practices, personal protective equipment, and procedures for clean-up of spills and leaks
- engineering control requirements
- emergency and first aid measures
- dates of MSDS preparation, edits, and update
- manufacturer contact information
The part that will be of most interest to patch testers is the ingredient information which is often incomplete but can provide guidance on patch testing workplace products in conjunction with DeGroot Patch Testing book.
- Usually patients require further patch testing after obtaining allergen information not on a MSDS.
- When the constituents listed on the MSDS total less than 100%, this should alert the physician that the manufacturer might have omitted materials they deem non-hazardous or proprietary
- If further information is required a phone call to the manufacturer using the phone number provided on the MSDS to inquire about missing information
| For all patient own products with the material safety data sheet, if you don’t know what it is then don’t test it. |
Recommended Reading
2021 Houle MC, Holness DL, DeKoven J. Occupational contact dermatitis: An individualized approach to the worker with dermatitis. Curr Dermatol Rep. 2021:1-10.
Videos to watch
Talk 27 Determining work relatedness
Talk 32 Exposure Assessment and MSDS
