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Learn Derm · Canonical curriculum

Foundations & Morphology.

Learn how to observe, describe, and organize skin findings before making a diagnosis.

For beginners, rotators, and refreshers. Describe what you see before deciding what it is.
Start with Lesion BasicsPractice Visual Description
Skin structure and morphology learning sequenceAn original educational diagram showing the epidermis, dermis, and subcutaneous layer beside flat, raised, fluid-filled, and deep lesion silhouettes.START WITH STRUCTUREEpidermisDermisSubcutisflat · raised · fluid · deep
Original DermPrep schematic. Diagram teaches relationships, not diagnosis.
PurposeBuild reliable morphology-first language.
CompetenciesRecognize · describe · compare · communicate.
PrerequisiteNone. Start here or after Start Here.
Builds towardVisual Diagnosis, cases, and clinic presentations.

Choose your depth

One foundation. Three ways in.

You can stop after any pathway and still leave with a usable framework.

Quick · 5 minutesGet the sequence

Structure, lesion family, and one complete sentence.

Core · 25–35 minutesBuild the language

Learn each descriptive dimension and compare common look-alikes.

Deep Dive · 15 minutes moreStrengthen reasoning

Connect morphology to localization, uncertainty, and differential thinking.

Quick mode · Your first win

Describe in this order.

  1. 1StructureWhere in or on the skin does the finding appear to live?
  2. 2Primary lesionFlat, solid and raised, fluid-filled, or deep?
  3. 3Secondary changeScale, crust, erosion, ulcer, fissure, or another change?
  4. 4Color + surfaceName the hue and what the surface does.
  5. 5Configuration + distributionHow lesions relate; where they occur.
  6. 6Depth + texture + evolutionPalpability, consistency, symmetry, and change over time.

Say it like this

“Multiple, symmetric, sharply demarcated, pink-brown plaques with overlying scale are distributed on the extensor elbows and knees.”

Remember: this sentence describes evidence. It does not independently establish a diagnosis.

Core · Step 1

Skin structure explains what you can see and feel.

The skin includes the epidermis and dermis over subcutaneous tissue. Morphology becomes easier when you ask whether a change is primarily superficial, epidermal, dermal, or deeper.

Surface

Stratum corneum

The outer barrier. Disruption may be visible as scale, fissuring, or erosion.

Why it matters: surface change can narrow a differential even when the base lesion is similar.

Epidermis

Cellular barrier

Provides a renewing barrier and contributes to pigmentation and immune surveillance.

Look for: color, thickness, surface change, and fluid-filled lesions.

Dermis

Support and sensation

Contains connective tissue, vessels, nerves, hair follicles, and glands.

Look for: edema, firmness, depth, temperature, and tenderness.

Subcutis

Deeper tissue

Adipose and connective tissue connect skin with underlying structures.

Look for: deeper nodules, mobility, tenderness, and overlying surface clues.

Core · Steps 2 and 3

Name the lesion, then name what changed.

For every term: what it is → what it looks like → what it is confused with → how to say it → why it matters.

Flat

Macule / patch

What: circumscribed color change without elevation or depression. “Patch” is commonly used for a larger area.

Confused with: thin plaque. Palpate for elevation.

Say: “a sharply demarcated brown patch.”

Solid + raised

Papule / plaque

What: a papule is a small palpable elevation; a plaque is a broader palpable elevation, often formed by enlargement or confluence.

Confused with: patch or nodule. Ask: is it raised, broad, or deep?

Say: “well-demarcated scaly plaques.”

Solid + deep

Nodule

What: a circumscribed, palpable lesion with substantial depth or substance.

Confused with: plaque. Depth matters, not size alone.

Say: “a firm mobile dermal nodule.”

Fluid-filled

Vesicle / bulla

What: circumscribed elevation containing fluid; “bulla” denotes a larger blister.

Confused with: pustule. Describe the apparent contents.

Say: “grouped clear vesicles on an erythematous base.”

Purulent material

Pustule

What: a circumscribed elevation containing purulent-appearing material.

Confused with: cloudy vesicle. Use context and examination.

Say: “follicular pustules.”

Transient edema

Wheal

What: a transient, edematous, raised lesion.

Confused with: plaque. Time course and edema help.

Say: “transient edematous wheals.”

Secondary change and surface language

ScaleFlakes or plates of stratum corneum.
CrustDried serum, blood, or purulent material.
ErosionSuperficial loss of epidermis; typically heals without scarring.
UlcerLoss extending into at least the dermis; may scar.
ExcoriationLinear or punctate change caused by scratching or rubbing.
FissureLinear crack extending into epidermis and sometimes dermis.
LichenificationThickened skin with accentuated lines, often after chronic rubbing.
AtrophyThinning of epidermis, dermis, or subcutaneous tissue.

Core · Steps 4 through 6

Complete the visual grammar.

Color

Use specific observed hues—pink, red, red-brown, violaceous, brown, black, blue-gray, white, yellow, or skin-colored—rather than assuming inflammation always appears bright red. Pair color with palpation, surface, symptoms, and surrounding skin.

Surface

Describe smooth, scaly, crusted, keratotic, verrucous, macerated, eroded, ulcerated, or other visible texture. Separate the base lesion from its surface change.

Configuration

How lesions relate: discrete, grouped, confluent, linear, annular, arcuate, reticular, targetoid, or another supported pattern.

Distribution

Where lesions occur: localized or generalized; symmetric or asymmetric; flexural, extensor, acral, intertriginous, dermatomal, photo-distributed, follicular, or another supported distribution.

Depth and texture

Palpation can add superficial versus deep, soft versus firm, fluctuant versus indurated, mobile versus fixed, warm, cool, tender, or non-tender.

Symmetry and evolution

Note whether findings mirror one another, whether lesions are in the same stage, and how they changed in size, number, color, surface, symptoms, or distribution over time.

Body-site terminology

ScalpFacePeriorbitalPerioralTrunkFlexuralExtensorIntertriginousAcralPalmarPlantarMucosalPeriungualGeneralized

Interactive comparison

Morphology Lab

Choose a pair. Predict the difference before revealing it.

The clue that separates them

Macule vs Patch

Macule

A flat, circumscribed color change.

Patch

A larger flat area of color change.

Ask: Is the finding palpable? If not, estimate and document its dimensions.

Say: “A 4 cm, sharply demarcated, light-brown patch on the left shoulder.”

Communication training

Morphology Builder

Build a model description—not an automated diagnosis.

Model description

Choose the features, then build your sentence.

Use responsibly: examine and document only findings you actually observe. A description supports communication; it does not replace history, examination, diagnostic testing, or supervision.

DermPrep method

Describe Before You Diagnose

SeeNotice objective features.
DescribeUse canonical language.
DifferentiateCompare plausible patterns.
DiagnoseIntegrate history, exam, and testing.

Clinical example

Observation

Multiple symmetric, well-demarcated plaques with scale on the extensor elbows and knees.

Differential thinking

Prioritize possibilities that fit a symmetric papulosquamous extensor pattern. Ask which history, nail, scalp, fold, medication, or testing finding would separate them.

Calibrated communication

“The morphology and distribution are most consistent with a papulosquamous process; I would examine the scalp and nails and discuss the focused differential with my supervising clinician.”

What changes your mind?

Mucosal involvement, pain, rapid progression, blistering, non-blanching change, systemic symptoms, medication timing, immune status, palm/sole involvement, nail findings, and evolution can substantially redirect the differential. Morphology is the start—not the whole conclusion.

Communication practice

Say it clearly enough to be useful.

Say It Like This

Patient-friendly

“I see several raised areas with a dry surface on both elbows.”

Student presentation

“There are multiple symmetric, sharply demarcated pink-brown plaques with scale on the extensor elbows.”

Reasoning language

“This pattern suggests a papulosquamous process; the distribution and associated findings will help prioritize the differential.”

What Would You Say?

Know / Say / Do

Know

The ordered descriptive dimensions and canonical morphology families.

Say

One objective sentence, followed by a prioritized interpretation with calibrated certainty.

Do

Inspect, palpate when appropriate, measure, compare sites, ask about evolution, and confirm with supervision.

Common mistakes

Correct the pattern—not just the word.

Patch = plaque

Correction: a patch is flat; a plaque is palpable. Look and palpate.

Scale = crust

Correction: scale is stratum corneum; crust is dried serum, blood, or purulent material.

Nodule = large papule

Correction: depth and substance help define a nodule; size alone is insufficient.

Erythema = purpura

Correction: erythema reflects increased blood flow and typically blanches; purpura reflects extravasated blood and does not.

Annular = targetoid

Correction: annular describes a ring; targetoid implies concentric zones.

Color alone proves inflammation

Correction: integrate surface, texture, warmth, edema, symptoms, evolution, and skin tone.

Deep Dive · Optional

Strengthen the reasoning underneath the words.

Why can reputable sources differ on size cutoffs?

Terminology systems and teaching references do not always use identical thresholds. DermPrep prioritizes the ILDS revised glossary and teaches size as a measured continuous feature rather than relying on a label alone. When precision matters, document the actual dimensions.

How should I describe color across skin tones?

Name the hue you observe and add surface, palpation, warmth, edema, symptoms, and comparison with surrounding skin. Inflammation may appear pink, red, red-brown, violaceous, dusky, or primarily as texture or pigment change. Avoid treating one skin tone as the default.

When is morphology insufficient?

Morphology narrows possibilities but may not establish a diagnosis. History, full examination, dermoscopy, microscopy, culture, biopsy, laboratory evaluation, or longitudinal change may be needed depending on the clinical question.

What is the difference between configuration and distribution?

Configuration describes how lesions are arranged relative to one another. Distribution describes where they occur across the body.

When to escalate

If a patient appears systemically unwell or has a painful or rapidly progressive eruption, extensive blistering or skin detachment, mucosal involvement, concerning non-blanching lesions, or another urgent feature, escalate promptly through the supervising clinical team.

Recommended learning path

Fifteen modules. One reproducible method.

Use the modules below to review the complete morphology and examination sequence.

Quick reference tools

Use the language at the point of need.

These tools use canonical terms and link back to the relevant lesson.

Morphology glossaryPrimary and secondary lesion languageComplete-description templateBuild one defensible sentenceCommonly confused termsCompare look-alike terminologyVisible versus palpableKnow what requires direct examinationSkin-tone considerationsUse color with surface, texture, and symptomsDescribe Before You DiagnosePractice morphology-first reasoning

Practice with canonical Question Bank filters

Move from learning to retrieval.

Practice sessions open only when eligible, reviewed questions and rights-cleared media are available. No duplicate question copies are stored here.

Practice This TopicQuick Pimp · MorphologyDescribe Before You DiagnoseVisual DiagnosisRapid Fire · TerminologyReview Missed MorphologyView Bookmarked Morphology

Connected inventory: approved question and rights-cleared image counts are unavailable until the canonical Question Bank and Media Library adapters are connected.

Retrieval practice

Try one question.

A learner sees a broad area of altered color. It is not palpable. Which description is strongest?

30-second recap

  • Start with structure and the primary lesion.
  • Separate the base lesion from secondary change.
  • Add color, surface, configuration, and distribution.
  • Use palpation to assess elevation, depth, texture, and tenderness.
  • Describe first; integrate history and testing before diagnosing.

Attending-style questions

Be ready to defend the description.

What is the primary lesion?

Name the lesion and the objective feature that supports it—flat versus raised, solid versus fluid-filled, superficial versus deep.

Is that scale or crust?

Scale represents stratum corneum; crust is dried exudate. State what you see and what supports the distinction.

Describe the distribution and configuration.

Say where the lesions occur, then separately describe how they are arranged.

What would you examine next?

Choose additional sites based on the pattern and focused differential—such as scalp, nails, mucosa, folds, palms, soles, or a complete skin examination when appropriate, consented, and supervised.

What finding would change your differential most?

Name one discriminating feature and explain how it raises or lowers specific possibilities.

Keep the learning loop moving

Your next best actions

PrerequisiteStart HereSee nextVisual DiagnosisPractice nextPimp Me · MorphologyApply nextClinical CasesPrepare nextRotation Ready
Sources & page information
  1. Nast A, Griffiths CEM, Hay R, et al. The 2016 International League of Dermatological Societies’ revised glossary for the description of cutaneous lesions. Br J Dermatol. 2016;174(6):1351–1358.
  2. International League of Dermatological Societies. Glossary for Dermatology Terms.
  3. American Academy of Dermatology. Basic Dermatology Curriculum.
  4. Agarwal S, Krishnamurthy K. Histology, Skin. StatPearls. NCBI Bookshelf.
  5. DermNet. Terminology in dermatology. Used as a tertiary cross-check.
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