Dermatology Terminology Flashcards
What is meant by a primary lesion?
a primary lesion is a lesion that appears as a direct result of the disease process
these are either flat or raised, and either small or big
What is meant by a “small” and “big” primary lesion?
- small refers to lesions that are <0.5cm in diameter
- big refers to lesions that are >0.5cm in diameter
What is the difference between a flat primary lesion and a raised primary lesion?
Flat lesion:
- cannot be palpated
- if you were to close your eyes and run your finger over the lesion, you would not know it was there
Raised lesion:
- a raised lesion is palpable
What is the name for a small, flat lesion?
macules
macules are small, flat lesions, such as freckles
What is a big, flat lesion called?
patch
a patch is a large, flat lesion, such as a port wine stain
What is a port wine stain?
a discolouration of the skin caused by a vascular anomaly (capillary malformation in the skin)
the colour is similar to port wine
this malformation is seen at birth (“birthmark”)
What is a small, raised lesion called?
papule
papules are small, raised lesions such as xanthomata
(yellow depositions of cholesterol-rich material in the skin)
What is the name of a large, raised lesion?
plaque
a plaque is a big, raised lesion, usually with a flat top, such as psoriasis plaques
What is a nodule?
a lesion that is large and raised, but also has a deeper component
e.g. pyogenic granulomas on the fingers
What is a pyogenic granuloma and what does it look like?
- a relatively common, reactive proliferation of capillary blood vessels
- presents as a shiny red lump with a raspberry-like or minced meat-like surface
- it is benign, but can cause discomfort & profuse bleeding
- found on the skin or inside the mouth
What is a vesicle?
a vesicle is a small, raised lesion that is also fluid-filled
e.g. vesicles are seen in chickenpox
What is a bulla?
a bulla is a large, raised lesion that is also fluid-filled
e.g. in an insect bite reaction
What is a pustule?
a pustule is a small, raised lesion that is filled with pus
e.g. on the cheeks of patients with acne
What is a crust?
a crust is dried exudate (e.g. blood, serum, pus) on the skin surface
What is a scale?
a scale is the accumulation or excess shedding of the stratum corneum
e.g. psoriasis plaques are often scaly
What is excoriation?
the loss of skin due to scratching or picking
What is lichenification?
lichenification occurs when the skin becomes thick & rubbery
there is an increase in skin lines & creases from chronic scratching or rubbing
What is a fissure?
a linear crack in the skin that is often very painful
this can extend all the way into the dermis
What is the difference between an erosion and an ulcer?
erosion:
- superficial open wound with loss of epidermis or mucosa only
ulcer:
- deep open wound with partial or complete loss of the dermis or submucosa
What is a wheal?
short lived (often < 24 hours), oedematous, well circumscribed papule or plaque seen in urticaria
What is telangiectasia?
dilated superficial dermal vessels
widened venules cause threadlike red lines on the skin, sometimes called “spider veins”
What is meant by fibrosis?
dermal scarring / thickening reactions
dermal fibrosis refers to excessive scarring of the skin as a result of a pathologic wound healing response
What is a keloid?
keloids are a type of raised scar that occur where the skin has healed after an injury
it overgrows the original wound boundaries and is chronic in nature
What is a comedone?
dilated hair follicles containing sebum/keratin
they are skin-coloured papules frequently found on the forehead and chin
open comedones are blackheads (black due to surface pigment - melanin)
closed comedones are whiteheads (the follicle is completely blocked)
What is a milium?
a small superficial cyst containing keratin
there are usually multiple and they present as tiny (< 1-2mm in size) pearly-white bumps just under the surface of the skin
What are petechiae?
small macules that are red or purple in colour, due to bleeding into the skin or mucous membranes
the rash will not blanch on pressure
What is purpura?
purpura occurs when small blood vessels burst, causing blood to pool under the skin
this creates red or purple flat lesions on the skin that range in size from small dots to large patches
(larger version of petechiae)
What are echymoses?
these involve larger extravasations of blood than purpura or petechiae
appears as a bruise-like patch
most common cause is capillaries being damaged by trauma, causing localised bleeding into surrounding interstitial tissues
What is onycholysis?
separation of the nail plate from the nail bed
painless detachment of the nail usually begins at the tip or the sides
What is pitting of the nail?
this describes punctate depressions of the nail plate
there are tiny dents in the nails
