Derm Cases · Dermatology / Contact allergy / Occupational skin disease
OSCE — patch testing work-up for occupational hand and eyelid eczema
An 8-minute OSCE on indications for patch testing, ESCD technique and reading schedule, ICDRG grading with relevance, series selection for a hairdresser, pitfall control (angry back, late reactors), and avoidance-centred counselling including PPD cross-reactivity awareness.
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Target exams
NEET-PGINICETPLABMRCPFRCDerm
Prompt
An 8-minute OSCE on indications for patch testing, ESCD technique and reading schedule, ICDRG grading with relevance, series selection for a hairdresser, pitfall control (angry back, late reactors), and avoidance-centred counselling including PPD cross-reactivity awareness.
Brief (to candidate)
You are in a contact dermatitis clinic. A hairdresser has chronic hand and eyelid eczema and a recent severe reaction after permanent hair dye. In 8 minutes, plan diagnostic patch testing and explain interpretation principles to the examiner (as if counselling the patient).
[1]Candidate instructions
- State indication for patch testing (not for pure ICD alone).
- Describe site, occlusion ~48 h, readings D2 / D3–D4 / D7.
- Outline ICDRG grades and relevance (present/past/unknown).
- Choose baseline + hairdressing/cosmetic/rubber-relevant supplements; mention PPD.
- Name one pitfall (angry back or steroid false negative) and one special test (ROAT or photopatch if photo pattern).
- Give a brief avoidance and barrier plan after results.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Indication | Chronic/recurrent occupational eczema ± dye flare → investigate ACD with patch testing; ICD may coexist but is not “proven” by a positive allergic grade[1][3] |
| Technique | Upper back; remove ~48 h; further reads including D7[1] |
| Grading | ICDRG IR / ?+ / + / ++ / +++ concepts[2] |
| Relevance | Grade ≠ diagnosis without exposure correlation |
| Series | Baseline + occupation/cosmetic (PPD, rubber accelerators, fragrances/preservatives as history dictates)[4] |
| Pitfalls / special | Angry back retest strategy; optional ROAT for leave-ons; photopatch only if photo pattern[1][5] |
| Communication | Written allergen names, PPE/wet-work changes, when to return if not improving |
Model key actions
- Explain type IV test purpose and schedule.[1]
- Prioritise PPD and workplace allergens in series selection.[3][4]
- Stress relevance + avoidance education after the report.
Common errors
- Reading only at chamber removal with no delayed visits.
- Treating every positive as currently causative.
- Forgetting D7 for metals/corticosteroids.
- Ordering photopatch for classic earlobe nickel without photo distribution.
- No occupational documentation or glove/PPE plan.
References5ShowHide
- [1]Johansen JD, Aalto-Korte K, Agner T, et al. European Society of Contact Dermatitis guideline for diagnostic patch testing - recommendations on best practice. Contact Dermatitis, 2015.PMID 26179009
- [2]Bruze M, Svedman C. Clarification and Modification of the International Contact Dermatitis Research Group Classification of Patch Test Reactions. Dermatitis, 2025.PMID 39773000
- [3]Scheinman PL, Vocanson M, Thyssen JP, et al. Contact dermatitis. Nature Reviews Disease Primers, 2021.PMID 34045488
- [4]Wilkinson SM, Gonçalo M, Aerts O, et al. The European baseline series and recommended additions: 2023. Contact Dermatitis, 2023.PMID 36443008
- [5]Gonçalo M, Ferguson J, Bonevalle A, et al. Photopatch testing: recommendations for a European photopatch test baseline series. Contact Dermatitis, 2013.PMID 23510344