Wednesday, April 14, 2021

What’s in a Name? A Refresher on Dermatologic Morphology

I had the opportunity during this selective to join an outpatient dermatology clinic. We managed patients with a variety of skin concerns from acne to basal cell carcinomas. I was reminded of the unique terminology used to describe various lesions and skin concerns that are used in dermatology. This post will contain a brief review on the terms used to describe dermatologic lesions.

 

How do describe a lesion:

  1. Primary Morphology
  2. Size
  3. Demarcation
  4. Colour
  5. Secondary Morphology
  6. Distribution

 

Primary morphology describes the general size classification, as well as whether the lesion is palpable (so you must feel the lesion!).

-       Flat Lesions (non-palpable):

o   Macule: flat (not palpable), smaller than 1 cm in size (think of a freckle)

o   Patch: flat (not palpable), larger than 1 cm in size (think of a flat birth mark)

-       Raised Lesions (palpable):

o   No deep component – confined mostly to the epidermis

§  Solid:

·      Papule: raised/solid swelling, smaller than 1 cm in size (think a mole)

·      Plaque: raised/solid swelling, larger than 1 cm in size (think of psoriasis)

§  Pus Filled:

·      Pustule: a raised swelling, smaller than 1cm in size, that is filled with pus (think of pimples)

·      Abscess, Faruncle, Carbuncle: a raised swelling, larger than 1 cm in size, named depending on the skin affected

§  Fluid Filled:

·      Vesicle: a raised fluid filled swelling, smaller than 1cm in size that is filled with fluid (think of a small blister)

·      Bulla: a raised, fluid filled swelling, larger than 1 cm (think of a large burn blister)

o   Deep Component – proliferation of cells in the mid-to-deep dermis

§  Nodule: has both a raised and deep component, smaller than 1 cm

§  Tumour: has both a raised and deep component, larger than 1 cm

 

2. Size: a self-explanatory part of the description, but try to be precise here, track down your ruler!

3. Demarcation: when we are looking at demarcation, we want to decide how well circumscribed the lesion is. If the lesion blends in with the surrounding tissue it is not well demarcated, if there is a clear border between the surrounding skin and the lesion is is well demarcated.

4. Colour: what colour is the lesion, is it skin-coloured, red, black? Are there multiple colours or is it all the same colour? 

5. Secondary Morphology: a description of other changes associated with the primary lesion, Examples:

  • Scale: excess keratin deposits from keratinocyte over-activity
  • Crust: dried blood, serum, or pus
  • Excoriations: superficial skin scratches
  • Fissures: deep line/break in skin
  • Erosions: break in skin at level of epidermis (doesn’t usually scar)
  • Ulceration: break through in skin through to the level of the dermis (secondary to rubbing of skin) - usually scars
  • Atrophy: thin skin from aging, sun exposure, inappropriate activity, topical steroids
  • Lichenification: thickened skin with increased skin markings, usually from chronic rubbing

6. Distribution: where is the lesion? On the face, back, hands? 

 

Example: Try describing the following lesion, using the principles described above. (answer found below references).



 

So, what’s in a name? When it comes to describing dermatologic morphology, a lot!

 

-KD-

 

References:

 

1. Approach to the Dermatologic Patient: Description of skin lesions. Merck Manual.https://www.merckmanuals.com/en-ca/professional/dermatologic-disorders/approach-to-the-dermatologic-patient/description-of-skin-lesions

2. Approach to the clinical dermatologic diagnosis. UpToDate. https://www.uptodate.com/contents/approach-to-the-clinical-dermatologic-diagnosis?search=dermatology%20morphology&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2#H4

3. Image: Medical News Today. https://cdn-prod.medicalnewstoday.com/content/images/articles/323/323152/psoriasis-on-persons-elbow.jpg

 

Answer:  Plaque, approximately 3cm x 2cm, well demarcated, pinkish red, with overlying silvery scale on the extensor surface of the elbow. What is it? Psoriasis!

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