Derm Cases · Dermatology / Therapeutics / Internal Medicine
OSCE — systemic immunosuppressants in dermatology: MTX, ciclosporin, azathioprine, mycophenolate
An 8-minute OSCE station on selecting and monitoring methotrexate, ciclosporin, azathioprine and mycophenolate for inflammatory dermatoses, pre-treatment screens, weekly versus daily MTX dosing safety, and key toxicities/interactions.
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Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on selecting and monitoring methotrexate, ciclosporin, azathioprine and mycophenolate for inflammatory dermatoses, pre-treatment screens, weekly versus daily MTX dosing safety, and key toxicities/interactions.
Brief (to candidate)
A 42-year-old with extensive psoriasis failed topical therapy and phototherapy. You are asked to start a conventional systemic agent. A second scenario mentions severe atopic dermatitis needing a rapid bridge. You have 8 minutes to choose agents, baseline tests, monitoring, and critical safety counselling.
[3]Candidate instructions
- Match MTX, ciclosporin, azathioprine, MMF to typical use cases.
- Emphasise methotrexate once weekly (never daily) + folic acid.
- List baseline labs/infection screens and monitoring cadence concepts.
- Name key toxicities and interactions.
- Cover pregnancy/fertility highlights (MTX/MMF).
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Methotrexate | First-line conventional systemic for many with moderate–severe psoriasis; 7.5–25 mg once weekly (not daily) + folic acid; monitor FBC/LFTs; counsel mucositis, marrow and liver risk; avoid concurrent trimethoprim-sulfamethoxazole carelessly[1][2] |
| Ciclosporin | Rapid control for severe psoriasis/AD flares; limit duration when possible; monitor BP and creatinine; multiple drug interactions; gingival hyperplasia, hypertrichosis, nephrotoxicity[1][3] |
| Azathioprine | Steroid-sparing in selected autoimmune dermatoses; check TPMT/NUDT15 where available; risk of marrow suppression and hypersensitivity; long-term infection/skin cancer vigilance with immunosuppression[4] |
| Mycophenolate mofetil | Useful in autoimmune blistering/connective-tissue dermatoses as steroid-sparing agent; teratogenic — robust contraception counselling; GI upset and cytopenias[5] |
| Shared pre-treatment | FBC, U&E, LFT, hepatitis/TB risk assessment as indicated, pregnancy test, vaccination history, medication review |
| Emergency stop advice | Unexplained fever, severe sore throat, dyspnoea, pregnancy, acute kidney injury symptoms on ciclosporin |
| Communication | Written dose day (especially MTX weekday), blood-test schedule, alcohol limits with MTX |
Model key actions
- Choose weekly methotrexate + folic acid with lab monitoring for chronic extensive psoriasis after shared decision-making.[1][2]
- Consider ciclosporin when rapid bridge needed, with renal/BP monitoring.[3]
- Flag MTX daily-dosing error risk and MMF/MTX teratogenicity.[5]
Common errors
- Prescribing daily methotrexate.
- No folic acid or monitoring plan.
- Ignoring hypertension/creatinine on ciclosporin.
- Starting azathioprine without TPMT strategy where available.
- Omitting pregnancy prevention for MTX/MMF.
References7ShowHide
- [1]Armstrong AW, Read C. Pathophysiology, Clinical Presentation, and Treatment of Psoriasis: A Review. JAMA, 2020.PMID 32427307
- [2]Butler DC, Berger T, Elmariah S, et al. Chronic Pruritus: A Review. JAMA, 2024.PMID 38809527
- [3]Chu DK, Schneider L, Asiniwasis RN, et al. Atopic dermatitis (eczema) guidelines: 2023 American Academy of Allergy, Asthma and Immunology/American College of Allergy, Asthma and Immunology Joint Task Force on Practice Parameters GRADE- and Institute of Medicine-based recommendations. Annals of Allergy, Asthma & Immunology, 2024.PMID 38108679
- [4]Ramos-Casals M, Brito-Zerón P, Bombardieri S, et al. EULAR recommendations for the management of Sjogren Annals of the Rheumatic Diseases, 2020.PMID 31672775
- [5]Clanner-Engelshofen BM, Bernhard D, Dargatz S, et al. S2k guideline: Rosacea. Journal der Deutschen Dermatologischen Gesellschaft (JDDG), 2022.PMID 35929658
- [6]Menter A, Gelfand JM, Connor C, et al. Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management of psoriasis with systemic nonbiologic therapies. Journal of the American Academy of Dermatology, 2020.PMID 32119894
- [7]Menting SP, Dekker PM, Limpens J, et al. Methotrexate Dosing Regimen for Plaque-type Psoriasis: A Systematic Review of the Use of Test-dose, Start-dose, Dosing Scheme, Dose Adjustments, Maximum Dose and Folic Acid Supplementation. Acta Derm Venereol, 2016.PMID 25721372