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Psoriasis
Psoriasis is a systemic inflammatory disease, not only a skin disease: beside the scaly plaques you look for arthritis, metabolic syndrome and heart disease — and treatment is chosen by extent, site and pregnancy plans.
Why it matters in the exam
The exam asks about drugs that worsen psoriasis (beta-blockers, lithium, antimalarials, steroid withdrawal), the move from topical to systemic treatment, a treatment that is safe in pregnancy, and the comorbidities. A patient whose psoriasis worsened in the last year — what changed in his medicines?
Remember that the two classic systemic drugs — methotrexate and acitretin — are teratogenic, and that latent tuberculosis is checked before a biologic.
Psoriasis accompanies patients for life, and the family doctor is the one who recognises and treats the comorbidities — blood pressure, diabetes, lipids, weight and depression — alongside the dermatologist. A simple question about joint pain and swelling at every visit allows psoriatic arthritis to be recognised before damage occurs.
Another question deals with the nails: pitting, separation of the nail from the bed and "oil-drop" spots point to psoriasis rather than fungus, and nail involvement is more often linked to arthritis. Other questions show several pictures of a rash with joint pain and ask which fits psoriasis. Remember the typical sites — elbows, knees, scalp, the umbilical area and the natal cleft — and the Koebner phenomenon, in which new plaques appear at a site of skin injury.
Key points
- Psoriasis is systemic: joints, metabolic syndrome, heart, depression.
- Mild — topical steroid and a vitamin D analogue.
- Worsened by: beta-blockers, lithium, antimalarials, steroid withdrawal.
- Moderate-to-severe — phototherapy, methotrexate, biologics.
- In pregnancy — topical treatment and phototherapy; methotrexate and acitretin are forbidden.
Summary table
| Extent and situation | First treatment | When there is no response | Exam note |
|---|---|---|---|
| Mild psoriasis (under 10% of body surface) | Topical steroid and a vitamin D analogue (calcipotriol) | Fixed combination of both | A combined product once daily |
| Face and folds | Mild steroid or a calcineurin inhibitor | — | A potent steroid causes skin atrophy |
| Scalp | Steroid gel or shampoo | — | Often with involvement elsewhere |
| Moderate-to-severe | Phototherapy (narrowband UVB), methotrexate | Apremilast, ciclosporin, acitretin | Methotrexate: folic acid, liver tests and blood count |
| Severe, joints or failure | Biologic: anti-TNF, IL-17, IL-23 | Switch biologic | Exclude latent tuberculosis before starting |
| Pregnancy | Topical steroid, narrowband UVB phototherapy | A selected biologic (certolizumab) | Methotrexate and acitretin are forbidden |
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
The full version is open to subscribers of: Family medicine, Medical licensing exam (IMLE), Dermatology and venereology, Internal medicine.
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Sources
- AAD–NPF joint guidelines, 2019–2021 — Management and treatment of psoriasis (topical, phototherapy, systemic, biologic; comorbidities)
- NICE clinical guideline CG153, 2012 (updated 2017) — Psoriasis: assessment and management
- Goroll AH, Mulley AG. Primary Care Medicine, 8th edition (2020) — Management of psoriasis
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.