Dermatology Examination Flashcards
Define the following terms:
- Acral distribution
- Extensor distribution
- Flexural distribution
- Follicular distribution
- Dermatomal distribution
- Seborrhoeic distribution
Acral distribution: distal areas including the hands and feet (e.g. hand, foot and mouth disease).
Extensor distribution: extensor surfaces including the elbows and knees (e.g. psoriasis).
Flexural distribution: flexural surfaces including the axillae, genital region and cubital fossae (e.g. eczema).
Follicular distribution: affecting areas with increased numbers of sebaceous glands such as the face, chest and axillae (e.g. acne).
Dermatomal distribution: the skin lesions appear confined to one or several dermatomes and do not cross the midline (e.g. herpes zoster).
Seborrhoeic distribution: present in areas where there is an increased density of sebaceous glands such as the face and scalp (e.g. seborrhoeic dermatitis).
Define the following terms:
- Discrete lesions
- Confluent lesions
- Linear lesions
- Discoid lesions
- Target lesions
- Annular lesions
Discrete lesions: individual lesions, clearly separated from one another (e.g. normal mole).
Confluent lesions: lesions that appear to be merging together (e.g. urticaria).
Linear lesions: lesions in the shape of a line (e.g. excoriations).
Discoid lesions: coin-shaped lesions (e.g. discoid eczema, discoid lupus).
Target lesions: concentric rings of varying colour, resembling a bullseye (e.g. erythema multiforme).
Annular lesions: ring-like lesions (e.g. tinea corporis).
Define the following terms:
- Erythematous lesions
- Purpuric lesions
- Hyperpigmented lesions
- Hypopigmented skin lesion
- Depigmentation
Erythematous lesions: redness of the skin caused by an increased blood supply to the area. Erythematous lesions will blanch when pressure is applied.
Purpuric lesions: reddish/purple discolouration of the skin caused by small blood vessels bleeding into the skin. Purpuric lesions do not blanch when pressure is applied. Petechiae are small purpuric lesions less than 2mm in diameter whereas ecchymoses are larger purpura more than 2mm across (commonly referred to as a bruise).
Hyperpigmented lesions: areas of darker skin caused by excess melanin production. Hyperpigmentation may be diffuse (e.g. Addison’s disease) or discrete (linea nigra in pregnancy).
Hypopigmented skin lesions: 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 hypopigmented skin lesions.
Depigmentation: areas of skin which appear completely white due to the absence of melanin. Vitiligo is an autoimmune condition that results in the destruction of melanocytes and loss of pigment in the areas of skin affected.
Define the following terms:
- Primary skin lesions
- Macule
- Patch
- Papule
- Nodule
- Plaque
- Vesicle
- Bulla
- Pustule
- Abscess
- Wheal
- Boil/furuncle
- Carbuncle
Primary skin lesions are those which develop as a direct result of a disease process.
Macule: a flat area of altered colour less than 1.5cm in diameter.
Patch: a flat area of altered colour greater than 1.5cm in diameter.
Papule: a solid raised palpable lesion less than 0.5cm in diameter.
Nodule: a solid raised palpable lesion greater than 0.5cm in diameter.
Plaque: a palpable flat lesion usually greater than 1cm in diameter. Most plaques are raised, however, some may be thickened without being visibly raised.
Vesicle: a raised, clear fluid-filled lesion less than 0.5cm in diameter.
Bulla: a raised, clear fluid-filled lesion greater than 0.5cm in diameter.
Pustule: a pus-containing lesion less than 0.5cm in diameter.
Abscess: a localised accumulation of pus.
Wheal: an 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 (i.e. multiple boils/furuncles)
Define the following terms:
- Secondary lesions are modifications of primary lesions that occur due to trauma to, or evolution of, the primary lesion.
- Excoriation
- Lichenification
- Scales
- Crust
- Scar
- Atrophic scarring
- Hypertrophic scarring
- Keloidal scarring
- Ulcer
- Fissure
- Striae (stretch marks)
*
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 with exaggeration of normal skin lines, typically caused by chronic rubbing or scratching of an area (e.g. chronic eczema).
Scales: visible fragments of the stratum corneum as it is shed from the skin, most commonly associated with psoriasis.
Crust: a 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 involves the thinning of normal tissues underlying the scar resulting in a cratering effect. Hypertrophic scarring involves the hyperproliferation of scar tissue within the wound boundary, resulting in a prominent scar. Keloidal scarring involves the hyperproliferation of scar tissue beyond the wound boundary resulting in a scar that is significantly larger than the original skin insult.
Ulcer: a localised defect in the skin of irregular size and shape where the epidermis and some dermis have been lost. Ulcers ultimately result in scarring when healed.
Fissure: a sharply-defined, linear or wedge-shaped tear in the epidermis with abrupt walls, typically due to excess skin dryness.
Striae (stretch marks): purple lines on the skin caused by tearing during the rapid growth or overstretching of skin (e.g. growth spurts, ascites, intrabdominal malignancy, Cushing’s syndrome, obesity, pregnancy). They undergo an evolution of colour from purple to pink to white as they mature.
What is the ABCDE approach to examining a pigmented skin lesion?
To perform a structured assessment of a pigmented lesion you should apply the ABCDE approach.³
ABCDE approach
Asymmetry
Assess the symmetry of the skin lesion: asymmetry is suggestive of malignancy.
Border irregularity
Assess the borders of the skin lesion: note if they appear well-defined. Poorly defined borders are suggestive of malignancy.
Colour variation or changes
Assess the colour of the skin lesion: note if the colour appears consistent throughout the lesion. The presence of multiple colours within a single skin lesion is suggestive of malignancy.
Diameter
Assess the diameter of the skin lesion: measure the size of the skin lesion and ask the patient if it has been growing in size. Progressively enlarging skin lesions, particularly those over 6mm in diameter are suggestive of malignancy.
Elevation/evolution
Assess the elevation of the skin lesion and take a history of the lesion’s evolution: elevated skin lesions and those which have a history of bleeding and itching are more concerning for malignancy.
What extra steps should you do if you suspect a lesion may be malignant?
If you identify a skin lesion which may be malignant you should perform a comprehensive assessment for other suspicious lesions and examine the regional lymph nodes.
When palpating a skin lesion you should note what charachterisitics?
Assess the surface characteristics of the lesion:
Texture: note if the lesion feels smooth (e.g. ecchymoses) or rough (e.g. psoriatic plaque).
Elevation: note if the lesion is flat (e.g. ecchymoses), raised (e.g. keratoacanthoma) or depressed (e.g. hypotrophic scar).
Crust: if present, assess if you are able to remove the crust and inspect the underlying tissue (e.g. psoriasis).
Temperature: assess the temperature of the lesions (e.g. an abscess may feel warm).
Assess the deeper characteristics of the lesion:
Consistency: note if the lesion feels hard, firm or soft.
Fluctuance: hold the lesion by its sides and then apply pressure to the centre of the mass with another finger. If the lesion is fluid-filled (e.g. cyst) then you should feel the sides bulging outwards.
Mobility: assess if the lesion feels mobile or is tethered to other local structures.
Tenderness: may indicate infective and/or inflammatory aetiology.
What further assessments/ investigations may you want to do upon completing a dermatology examination?
Suggest further assessments and investigations to the examiner:
Perform relevant examinations of any systems that may be related to dermatological findings (e.g. local lymph node assessment).
Swabs/skin scrapings of lesions: for microbiology, virology and fungal culture.
Dermatoscopy of lesions: to more accurately assess a skin lesion (particularly melanocytic or vascular lesions).
Perform a biopsy of the skin lesion: for histological analysis.
