Examining a skin lesion - OSCE guide

Examination of a skin lesion frequently appears in OSCEs. You’ll be expected to pick up the relevant clinical signs using your examination skills. This guide provides a clear step by step approach to examining a skin lesion in an OSCE setting. Check out the examination of a skin lesion (dermatological exam) mark scheme here.

Introduction

Wash hands

Introduce yourself

Confirm patient details – name / DOB

Explain the examination

Gain consent

Expose the lesion(s) and ensure the patient is comfortable

Obtain a chaperone if a lesion is present in an intimate area

General inspection

Around the bed

Note any clues around the bed as to a diagnosis – e.g. medication/creams

The patient

Observe if the patient appears comfortable at rest

Observe the number of skin lesions

Observe the location and distribution of any skin lesions:

Acral – affecting distal areas, hands and feet
Extensor – extensor surfaces, elbows, knees
Flexural – flexural surfaces, axillae, genital areas, cubital fossa
Follicular – arising from hair follicles
Dermatomal – corresponding with nerve root distribution
Seborrhoeic – associated with areas where there are sebaceous glands, face and scalp

Close inspection of individual lesions

Size of the lesion

Assess the size of the lesion – width/height (if raised)

Configuration of the lesion(s)

Configuration refers to the shape or outline of skin lesions. The pattern of multiple lesions or shape of an individual lesion can assist in diagnosis.

Assess if the lesion is discrete or confluent

Assess the shape of the lesion(s)

Assess the border of the lesion(s) – well defined vs poorly defined

Types of configurations

Discrete lesions – individual lesions, clearly separated from one another

Confluent lesions – lesions that appear to be merging together

Linear lesions – e.g. scratching related lesions

Discoid (coin shaped) – discoid eczema/discoid lupus

Target lesions – concentric rings of varying colour – resembles a bullseye – erythema multiforme

Annular – ring like lesions

Colour of the lesion

Assess the colour of the lesion

Types of colours

Erythema:

Redness of the skin
Caused by increased blood supply
Blanches when pressure is applied to it

Purpura:

Reddish/purple discolouration of the skin
Caused by bleeding into the skin
Do not blanch when pressure is applied

Types of purpura include:
- Petechiae – small red/purple spots on the skin (<2mm in width)
- Ecchymosis – larger red/purple lesions (>2mm) – commonly referred to as a bruise

Hyperpigmentation:

An increased amount of melanin production results in hyperpigmentation of the skin
It can be diffuse or focal and has many causes

Hypopigmentation:

Areas of paler skin caused by melanocyte and melanin depletion or dysfunction.
Pityriasis versicolour is a superficial fungal infection of the skin that impairs melanocyte function resulting in hypopigmentation.

Depigmentation:

Depigmentation describes the absence of melanin within the skin resulting in the skin appearing completely white.
Vitiligo is an autoimmune condition that results in the destruction of melanocytes and therefore the loss of pigment in the areas of skin affected.

Morphology

Assess the form and structure of the lesion:

Is the lesion flat, raised above the plane of skin or depressed below the plane of skin?

Primary lesions

Macule – a flat area of altered colour <1.5cm in diameter

Patch – a flat area of altered colour >1.5cm in diameter

Papule – solid raised palpable lesion <0.5cm in diameter

Nodule – solid raised palpable lesion >0.5cm in diameter

Plaque:

palpable flat lesion usually >1cm in diameter
most are raised, but some may just be thickened without being visible raised
its borders may be well defined or poorly defined

Vesicle – raised, clear fluid filled lesion <0.5cm in diameter

Bulla – raised, clear fluid filled lesion >0.5cm in diameter

Pustule – pus containing lesion <0.5cm in diameter

Abscess – localised accumulation of pus

Wheal – oedematous papule or plaque caused by dermal oedema.

Boil / furuncle – staphylococcal infection around or within a hair follicle

Carbuncle – staphylococcal infection of adjacent hair follicles (multiple boils/furuncles)

Secondary lesions

Secondary lesions are modifications of primary lesions that occur due to trauma to, or evolution of, the primary lesion.

Excoriation – loss of epidermis associated with trauma

Lichenification:

Thickening of the epidermis seen with exaggeration of normal skin lines
It is usually due to chronic rubbing or scratching of an area

Scales:

Visible fragments of the stratum corneum as it is shed from the skin
Most commonly associated with psoriasis

Crust:

Rough surface consisting of dried serum, blood, bacteria and cellular debris
The serum, blood, bacteria and debris has usually exuded through an eroded epidermis

Scar:

New fibrous tissue which occurs after skin injury
Atrophic scarring – thinning of the normal tissue
Hypertrophic scarring – hyperproliferation of scar tissue within the wound boundary
Keloidal scarring – hyperproliferation of scar tissue beyond the wound boundary

Ulcer:

Localised defect in the skin of irregular size and shape where epidermis and some dermis have been lost
Results in scarring

Fissure:

Sharply-defined, linear or wedge-shaped tears in the epidermis with abrupt walls
Usually due to excess dryness

Striae:

Often referred to as stretch marks
Evolution in colour = Purple -> Pink ->White
Associated with growth spurts, excess steroid use or production and pregnancy

Assessment of a pigmented lesion

If lesion is pigmented use the ABCDE assessment method³

Asymmetry more suggestive of sinister pathology

Border irregularity

Are the edges of the lesion well defined?
Less defined borders are more suggestive of sinister pathology

Colour variation or changes:

Is the colour consistent?
Two or more colours within one lesion is more suggestive of sinister pathology

Diameter:

Has there been a change in size of the lesion?
Increasing size, particularly over 6mm diameter is more concerning

Elevation/evolution:

Changes in colour, size, symmetry, surface characteristics, and symptoms.
Symptoms include itching, bleeding and scabbing of the lesion

If you feel a lesion is concerning you should perform a comprehensive systematic examination of other areas:

- Inspect the rest of the skin for suspicious pigmented lesions or dysplastic naevi
- Palpate major lymph nodes in the regional drainage area

Palpation of skin lesions

Don gloves if the skin lesion is felt to be infective or is likely to expose you to bodily fluids (e.g. blood/pus).

Assess surface characteristics of the lesion

Texture – smooth/rough – e.g. roughness in hyperkeratosis (scales)

Flat, raised or depressed?

Crust – if present, are you able to remove crust and see what is underneath?

Temperature – is the lesion warm?

Assess deeper characteristics of the lesion

Consistency – hard/soft/firm/fluctuant

Mobility – is the lesion attached to the underlying/overlying tissue?

Tenderness – is the lesion tender on palpation?

Systemic examination

Nails, hands and elbows

Assess the nails, hands and elbows for signs associated with dermatological disease

Examples of nail signs

Nail pitting:

Punctate depressions of the nail plate
Associated with eczema, psoriasis and alopecia areata

Onycholysis:

Separation of the distal end of the nail plate from the nail bed
Associated with psoriasis and fungal nail infection

Koilonychia:

Spoon shaped indentation of the nail plate
Associated with iron deficiency anemia, can also be congenital

Nail clubbing:

Loss of the angle between the posterior nail fold and nail plate
Associated with many conditions including inflammatory bowel disease, cyanotic heart disease, lung cancer, bronchiectasis

Elbows:

Xanthomas – secondary to underlying hyperlipidaemia
Psoriasis plaques on elbows

Read more about nail changes, with included images here

Hair and scalp

Inspect the hair and scalp

Examples of pathology

Loss of hair:

Alopecia areata – well defined patches of hair loss with surrounding normal hair
Alopecia totalis – loss of all hair from the scalp (affects 5% of those with autoimmune hair loss)
Read more here

Excess hair:

Hirsutism – androgen dependent excess hair growth in females
Hypertrichosis – non-androgen dependent excess hair growth

Scalp:

Psoriasis plaques
Dandruff – e.g. seborrheic dermatitis

Mucous membranes

Inspect oral mucosa to evidence of skin disease (e.g. pigmented lesions/bullae)

To complete the examination…

Thank patient