Skin Examination

How to examine the skin. A system for doctors, medical student finals, OSCEs and MRCP PACES

Introduction

• Skin complaints are common in clinical exams and everyday practice
• Skin cancers are increasing in prevalence and – if detected early – treatment may be curative
• Cutaneous signs can also be vital in identifying systemic diseases
• With a structured examination technique and a little knowledge of terminology (see below), skin signs can be described and classified systematically

 

Preparation (WIIPPPPE)

• Wash your hands
  • You should wear gloves if the condition is weeping or likely to be contagious
• Introduce yourself
• Identity of patient (confirm)
• Permission (consent and explain examination)
• Pain?
• Privacy
• Exposure
  • Remember that some conditions require access to certain areas (e.g. the elbows and scalp in psoriasis; the soles in palmoplantar pustular psoriasis)

 

Before examining, remember how you will try to describe the lesions… 

How to describe skin lesions

Lesion	Description	Example
Primary Lesions
Macule	<0.5cm, flat, circumscribed area of altered skin colour	Vitiligo (small)
Patch	≥0.5cm, flat, circumscribed area of altered skin colour	Vitiligo (large)
Papule	<0.5cm, circumscribed elevation of skin	Molluscum contagiosum
Plaque	≥0.5cm, circumscribed elevation of skin	Psoriasis
Weal	Transient, smooth, slightly raised lesion, characteristically with a pale centre and a pink margin	Urticaria
Vesicle (blister)	<0.5cm, circumscribed, fluid-containing elevation	Acute eczema e.g. pompylox
Bulla (blister)	≥0.5cm, circumscribed, fluid-containing elevation	Burn, friction
Pustule	Visible collection of pus	Staphylococcal folliculitis
Abscess	Localised collection of pus in a cavity	Bacterial infection
Erythema	Redness, blanching	Erythema nodosum
Purpura	Redness, non-blanching, secondary to collections of red blood cells	Vasculitis, platelet or clotting defect
Telangiectasis	Dilated capillaries visible on the skin surface	Side-effect of topical steroids
Secondary Lesions
Scale	Thickened, loose, readily detached fragments of stratum corneum	Psoriasis
Crust	Dried exudate	Impetigo

Also consider how you will describe the distribution of lesions… 

Position of skin lesions

Inspection

• Before starting
  • Some lesions may be seen more easily with side-lighting than direct illumination. A supplementary adjustable light source is therefore useful
  • Cover sensitive areas such as breasts and genitalia once they have been inspected
• At the bedside
  • Check the bedside for tubes of ointment or tubs of emollient (are they being used?)
  • What is prescribed on the drug chart (many rashes are caused by drugs) and is it being taken?
• The patient
  • General
    • Does the patient look well? Is he/she scratching or displaying other signs of distress?
    • Inspection should include the nails, the scalp, the hair and the mucous membranes (inside the mouth)
  • Basics of rash description
    • Distribution (symmetry)
      • Is it symmetrical suggesting a systemic (endogenous) aetiology or asymmetrical suggesting an external cause e.g. infection, trauma, contact dermatitis?
      • Does the rash involve particular sites e.g. extensor or flexural, sun-exposed or covered?
      • Do lesions adopt any particular pattern e.g. diffuse, linear, grouped or scattered (see below)?
      • Examine scars as some problems arise in previously damaged skin (the Koebner phenomenon).
    • Colour
      • What colour is the affected skin – red, purple, brown?
      • Do lesions leave pigment change (increased or decreased) or scars?
    • Shape and size
    • Border
      • Is the border well-demarcated or indistinct?
      • Ask the patient to indicate early and late lesions.
      • Decide what is primary or secondary and how lesions evolve or spread.
  •  Specifics of rash description
    • Excoriation
      • Look for linear scratch marks (excoriations) indicative of itching (pruritus)
    • Ulcer/erosion
      • Is the skin eroded (superficial epidermal loss) or ulcerated (dermal damage)?
    • Weeping
    • Crusting, hyperkeratosis or scale
    • Blood vessels
      • Are blood vessels easily visible suggesting skin atrophy or increased superficial vasculature (telangiectasia)?
    • Odour
      • Foul-smelling ulcers may be infected with anaerobes or Pseudomonas aeruginosa. Some rashes smell unpleasant e.g. Darier disease

 

Descriptive terms for the shape of skin lesions

Terminology	Pattern of lesions
Grouped
Linear
Serpiginous (wavy)
Arcuate (curved)
Nummular/discoid (coin like)
Annular (ring-like)

Palpation

• Tenderness (ask the patient first!)
  • In the elderly, patients taking systemic steroids or patients with rheumatoid arthritis, the skin may exceptionally fragile
• Surface texture
  • The surface texture of lesions can be assessed by running a finger over the top of a lesion to feel if the skin is smooth or rough (hyperkeratotic)
• Scaling
  • If scaling is not easily visible, lightly scrape a lesion with your fingernail to establish whether there is any scaling (indicating epidermal involvement)
• Elevation
  • Are lesions raised (palpable) or flat or does the patient have both raised and flat lesions (a maculopapular rash)?
• If the skin is red:
  • Check if this is an erythema (blanching with light pressure)
  • Purpura (nonblanching) is caused by leakage of blood into the perivascular dermal tissues
    • Flat purpura suggests leakage without inflammation and may be indicative of inadequate dermal elastic tissue e.g. atrophic elderly or sun damaged skin or a coagulation disorder
  • Palpable purpura  suggests associated inflammation and is likely to be caused by a small-vessel cutaneous vasculitis such as Henoch-Schonlein purpura
• Skin thickness and depth of involvement
  • Is there any atrophy (tissue loss) with wrinkling or dimpling (loss of fat)?
  • Does the problem involve the dermis or do you think it extends more deeply into the fat (panniculitis)?
  • Press gently to assess the firmness of lesions to distinguish between solid lesions and those that are filled with fluid
• Tethering
  • Gently pinch the skin or try to pick up lumps between finger and thumb to assess depth. Is there any tethering to underlying tissues?
• Check for associated signs
  • Feel the temperature of involved skin and compare with normal
    • Inflamed skin e.g. cellulitis is hot while poorly perfused skin is cold
  • Is there extending erythema associated with oedema or crepitus
    • Crepitus is the sound produced when palpating skin with bubbles of gas beneath. This can indicate necrotising fasciitis or gas gangrene

 

Examining Pigmented Lesions

• Skin cancer is the commonest cancer and any examination of the skin should include a check for sun damage and potential skin malignancy
• Malignant melanoma must be distinguished from more common pigmented lesions such as:
  • Seborrhoeic warts (common in the elderly)
  • “Sunspots” (solar lentigines)
  • Benign melanocytic naevi (moles)
    • The “ugly duckling” sign may help when examining patients with many melanocytic naevi (moles): a “mole” that stands out and looks very different from the surrounding moles should be checked particularly carefully to exclude malignancy
• Two methods have been advanced to assist in diagnosing malignant melanoma: ABCD(E) and the revised 7-point checklist

 

Diagnosing melanoma - the ABCDE and revised 7-point system

ABCD(E) system	Revised 7-point checklist
Asymmetry	Major criteria (2 points each)
Border irregularity	Change in size
Colour variation	Change in shape
Diameter >6mm	Change in colour
Evolution over time	minor criteria (1 point each)
	Inflammation
	Crusting/bleeding
	Sensory change
	Diameter ≥7mm
Refer to a dermatologist if a lesion has ≥1 of the above	Refer to a dermatologist if a lesion scores ≥3 points

Any patient with a suspicious lesion should be seen by a dermatologist who may extra equipment (e.g. a dermatoscope) to assess it further…

 

Extra Equipment

• Wood’s Light
  • A Wood’s light emits UVA radiation and accentuates some forms of hypo- or hyperpigmentation
  • Wood’s light also detects some skin infections e.g. erythrasma fluoresces coral red, some fungal infections glow green
• Dermatoscopes
  • Dermatoscopes magnify skin signs such as nail fold capillaries  or scabies burrows but are most often used to differentiate benign from malignant pigmented lesions
    • Features that indicate malignancy include irregular dots of pigment, irregular peripheral extensions of the lesion (pseudopods) and a blue-white veil around the periphery of the lesion

Views of a melanoma with the unaided eye (A) and with a dermatoscope (B) showing irregular dots of pigment, irregular peripheral extensions (pseudopods) and a blue-white veil [the scale shown is in millimetres]

 

Complete the examination

• Thank the patient after finishing the examination
• Make sure they are comfortable and happy getting dressed
• Wash or use alcohol gel on your hands
• Turn to the examiner to present your findings…

 

Summary of skin examination

• Inspection
  • Around the bedside
  • The patient
    • Basics of rash description
      • Site; shape; size; symmetry
      • Colour
      • Border
    • Specifics
      • Excoriation
      • Ulcer/erosion
      • Weeping
      • Crusting, hyperkeratosis or scale
      • visibility of blood vessels
      • Odour
• Palpation
  • Tenderness (ask the patient first!)
  • Surface texture
  • Elevation
  • Skin thickness
  • Blanching
  • Tissue loss
  • Tethering
  • Associated signs
    • Temperature
    • Oedema
    • Crepitus
• Extra tests
  • Wood’s lamp
  • Dermatoscopy
• Thank the patient

 

Click here to learn about the hand examination and here for the lump and bump examination

Perfect revision for medical student finals, OSCES and PACES