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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
RapidMLAMSRAGP

Primary and secondary lesion morphology

Essential points for quick revision.

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Escalate

Escalate urgently when assessment for Primary and secondary lesion morphology reveals systemic toxicity, airway or eye involvement, extensive skin failure, a non-blanching eruption in an unwell patient, or a rapidly changing lesion suspicious for aggressive malignancy.

Synopsis

Describe skin lesions precisely using reproducible primary and secondary morphology, recognise changes caused by evolution or manipulation, and communicate findings without relying on colour alone.

  • Primary lesions include macules, patches, papules, plaques, nodules, vesicles, bullae, pustules, wheals and cysts; measure rather than estimating their size.
  • Secondary change includes scale, crust, erosion, ulceration, excoriation, fissure, atrophy, lichenification and scar, and may obscure the initiating lesion.
  • Describe colour with morphology and palpation: erythema may appear bright red, violaceous, dusky, brown or grey depending on pigmentation and inflammation depth.

Key red flags

A rapidly spreading painful eruption, dusky skin, blistering, mucosal erosion or systemic illness requires urgent assessment rather than prolonged descriptive refinement.

Surface loss

Erosion is epidermal loss and usually heals without scar; ulceration extends into dermis and demands a cause, depth and edge description.

Investigation priorities

01
Inspection under diffuse lightFirst step

Define the dominant primary lesion and surface change.

Management branches

Planned assessmentUse structured morphological description systematically

The patient is stable and the result will alter diagnosis, referral or follow-up.

  1. Define the question for Primary and secondary lesion morphology, explain the process and obtain valid consent before exposing, touching, photographing or sampling skin.
  2. Choose representative anatomy, optimise lighting or specimen technique, and document site, morphology, symptoms and relevant previous treatment.
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Sources and review status3 sources · checked 27 Aug 2026 · clinical review pending
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom