General skin examination

  • Colour
    • Uniform or variegated
    • Pallor
    • Erythema
    • Cyanosis
    • Jaundice
    • Pigmentary abnormalities
      • Hyperpigmentation
      • Hypopigmentation
      • Depigmentation (e.g. vitiligo)
    • Skin type (see Hx section under HPI Mole Changes)
  • Moisture
    • Scaling
    • Dryness

Inspection of skin lesion (SCALDA mnemonic)

  • S = Size
  • C = Colour
Colour Examples
Blue Mongolian spot, benign blue nevus
Yellow Xanthoma, jaundice
Violet Lichen planus, lupus erythematosus, dermatomyositis
Red Psoriasis, cherry hemangioma
Brown Hemosiderin
White Lichen sclerosus
Black Ink (tattoo), melanin
  • A = Arrangement (configuration)
Arrangement Description Examples
Nummular Coin-like Nummular eczema
Annular Ring-like Granuloma annulare, tinea, urticarial
Linear Line-like Arthropod bites, striae, poison ivy
Grouped Discrete lesions in localized areas Herpes zoster, herpes simplex
Serpiginous Snake-like Cuteaneous larva migrans
Retiform Net-like Wickham's striae in lichen planus
Confluent Merging together Psoriasis, drug rash
  • L = Lesion morphology

Primary Lesions

Lesions Description Examples
Macule Flat lesions, <1cm Freckles, cafe-au-lait
Patch Flat lesions, >1cm Vitiligo, port wine stain
Papule Palpable, superficial lesion, <1cm Basal cell carcinoma
Plaque Palpable, superficial lesion, >1cm Psoriasis, eczema
Nodule Palpable, deep lesion, <1cm Erythema nodosum
Tumour Palpable, deep lesion, >1cm Lipoma
Wheal Irregular, transient, edematous (disappears in 24-48 hours) Urticaria, dermatographism
Vesicle Palpable, filled with serous fluid, <1cm Herpes simplex
Bulla Palpable, filled with serous fluid, >1cm Bullous pemphigoid
Pustule Palpable, filled with purulent material Acne, impetigo, pustular psoriasis
Cyst Nodule, filled with fluid or semisolid material Epidermal inclusion

Secondary Lesions

Secondary Lesions Description Examples
Crust Dried residue of serum, pus or blood Impetigo
Erosion Loss of superficial epidermis, heals without scar Abrasion, TEN, scalded skin
Ulcer Deeper loss of epidermis and dermis, heals with scar Venous insufficiency, arterial insufficiency, malignancy
Fissure Linear crack in skin Tinea pedis
Scar Fibrous replacement tissue, may be atrophic or hypertrophic Keloid
Scale Thickened stratum corneum resulting in flakes of epidermis Seborrheic dermatitis, psoriasis, cutaneous t cell lymphoma
  • D = Distribution
    • Dermatomal (following a dermatome)
    • Symmetrical/asymmetrical
    • Flexural (involving body)
    • Extensor (involving extensor surface of limbs)
    • Follicular (arising from hair follicle)
  • A = Adjacent structures
    • Hair
      • Alopecia (hair loss)
      • Hirsutism
      • Hair pull test (>6 hairs is considered abnormal in a person who has washed their hair that morning)
      • Coarse (hypothyroidism) or fine (hyperthyroidism)
    • Nails
      • Hyperkeratosis
      • Oil staining
      • Pitting
      • Colour change
      • Splitting, breaking, or lifting off of nail bed (onycholysis)
    • Mucous membranes
      • Ulcers
      • Tongue
      • Genitalia (when indicated)


Special Tests

Consider the following special tests:

Mohs Surgery

Named after Dr. F Mohs, Mohs surgery refers to the surgical technique by which skin cancers are excised as completely as possible. This occurs through the employment of tangential cutting and frozen-section histology. With Mohs surgery, microscopic examination of the margins of excised specimens is employed to ensure affected tissue is removed as completely as possible, while leaving healthy tissue intact.

Performing the Skill

  • Fresh-tissue technique. Most commonly performed
    • Treatment of choice for lesions on the face and neck
    • Ideal for recurrent or aggressive lesions
    • Tumors are excised at 45 degree angles. Light microscopy employed subsequently for identification of residual neoplasm
  • Procedure
    • Mark area of interest
    • Administer local anesthetic
    • Mark the tumor for precise orientation
    • Debulk superficial portion of tumor with curette
    • Excise tumor
      • With scalpel at 45 degree angle
      • Angle scalpel underneath the skin so deep margins are excised horizontally
      • Excise lesion in its entirety
    • Promote and achieve hemostasis at site of excision
    • Draw map of where lesion was removed from patient
    • Divide the excised specimen into quadrants
    • Orient dermis upward and flatten specimen
    • Color code edges of excised lesions with tissue dyes
    • Mount and freeze specimen
    • Place specimen on slide
    • Stain specimen with hematoxylin-eosin or toluidine blue
    • Mark any residual neoplasm on the 2D map and remove residual neoplasm
    • Repeat freezing and staining process to ensure total neoplasm removal
    • Reconstruct defect

  • Fixed-tissue technique: aka chemosurgery. (Used nonfrequently)
    • Similar to fresh-tissue technique, however, tissue fixation achieved with zinc chloride paste prior to excision
    • Eliminates need for anesthesia
    • Creates blood-free field
  • Procedure
    • Mark area of interest
    • Mark the tumor for precise orientation
    • Debulk superficial portion of tumor with curette
    • Apply dichloroacetic acid
    • Apply zinc chloride paste and cover with occlusive dressing for 6-24 hours
    • Continue to excise tumor as you would with fresh-frozen technique
      • Scalpel at 45 degrees
      • Angle scapel underneath the skin so deep margins are excised horizontally
      • Excise tumor in its entirety
    • Examine tissue under microscope
    • Apply additional zinc chloride paste to residual tumor and cover for 6-24 hours
    • Excise residual tumor (limit to one stage of excision per day)
    • Once tumor free, allow remaining tissue previously covered with zinc chloride to slough off (may take several days)
    • Repair and reconstruct defect

Indications, Limitations, Complications

  • Indications
    • Aggressive histologic growth pattern
    • Lesions at anatomical locations where other modalities will likely result in recurrence
    • Lesions at anatomical locations that require conservation of tissue
  • Limitations
    • Can take a long time, especially if the case is complex
    • Requires a specially trained dermatologist and staff
    • Recurrence is still possible (especially in case of non-contiguous neoplastic growth)
    • Adjunctive therapy may still be necessary for treatment of malignancy
  • Complications
    • Bleeding (anticoagulants)
    • Damage to nerves
    • Possiblity of infection


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