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.
Confirm patient details – name / DOB
Explain the examination
Expose the lesion(s) and ensure the patient is comfortable
Obtain a chaperone if a lesion is present in an intimate area
Around the bed
Note any clues around the bed as to a diagnosis – e.g. medication/creams
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
- Redness of the skin
- Caused by increased blood supply
- Blanches when pressure is applied to it
- 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
- An increased amount of melanin production results in hyperpigmentation of the skin
- It can be diffuse or focal and has many causes
- 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 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.
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?
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
- 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 are modifications of primary lesions that occur due to trauma to, or evolution of, the primary lesion.
Excoriation – loss of epidermis associated with trauma
- Thickening of the epidermis seen with exaggeration of normal skin lines
- It is usually due to chronic rubbing or scratching of an area
- Visible fragments of the stratum corneum as it is shed from the skin
- Most commonly associated with psoriasis
- Rough surface consisting of dried serum, blood, bacteria and cellular debris
- The serum, blood, bacteria and debris has usually exuded through an eroded epidermis
- 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
- Localised defect in the skin of irregular size and shape where epidermis and some dermis have been lost
- Results in scarring
- Sharply-defined, linear or wedge-shaped tears in the epidermis with abrupt walls
- Usually due to excess dryness
- 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
- 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
- Has there been a change in size of the lesion?
- Increasing size, particularly over 6mm diameter is more concerning
- 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?
Nails, hands and elbows
Assess the nails, hands and elbows for signs associated with dermatological disease
- Punctate depressions of the nail plate
- Associated with eczema, psoriasis and alopecia areata
- Separation of the distal end of the nail plate from the nail bed
- Associated with psoriasis and fungal nail infection
- Spoon shaped indentation of the nail plate
- Associated with iron deficiency anemia, can also be congenital
- 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
- 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
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
- Hirsutism – androgen dependent excess hair growth in females
- Hypertrichosis – non-androgen dependent excess hair growth
- Psoriasis plaques
- Dandruff – e.g. seborrheic dermatitis
Inspect oral mucosa to evidence of skin disease (e.g. pigmented lesions/bullae)
To complete the examination…
Suggest further assessments and investigations:
- Perform relevant examinations of any systems that may be related to dermatological findings
- Swabs/skin scrapings of lesions – microbiology/virology/fungal culture
- Dermatoscopy of lesions – melanocytic and vascular lesions
- Biopsy of lesions
1. British Association of Dermatologists. Handbook for Medical Students and Junior Doctors. Published 2014. Available [HERE]2. Dermnet New Zealand. Dermatology terminology. Published 1997. Revised 2017. Available [HERE]
3. NICE – Clinical Knowledge Summaries. Melanoma and pigmented lesions. Revised March 2011. Available [HERE]