Rash Morphology Flashcards
Layer of the epidermis
Epidermis
Dermis
Hypodermis
Basement membrane
Subcutaneous Fat
Fibroblasts produce collagen
4 major cells types = keratinocytes, langerhans cells, melanocytes, Merkel cells
Layers of the epidermis
come lets get some beer
corneum = dead keratinocytes lucidum = palms and soles, extra skin layer, more resilient skin granulosum = lipids and lamellar granules spinosum = langerhan cells (APC), basale = melanocyte, where keratinocytes are produced (journey takes 30 days to go up the layers), Merkel cells
morphology into size
middle = fissures
top right = lichenification (thickening, seen in eczema)
bottom right = excoriations (scratch marks, seen in eczema)
left = ulcer (epidermal loss)
zmacule
flat lesion <1cm, without elevation or depression
BLEEDING = petechia, purpura (macula or palpable), ecchymosis
VASCULITIS
ix = clotting screen, FBC for anaemia, LFT
patch
larger than 1cm, flat
What morphology is this?
maculopapular nodule
what are these?
HSV on the left (vesicle)
acne on the right (pustule)
bullous pemphigoid
vesicle, bullae and pustule
plaques
abscess, wheal and papilloma
abscess = localised collection of pus in a cavity, more than 1cm in diameter
wheal = elevated compressible fading area (dermal oedema)
papilloma = small projection of skin
configuration (shape)
annular means leading red edge
erythema multiforme
- hypersensitivity reaction
- common culprit: HSV (1 >2)
- other: mycoplasma pneumonia
- hands/palms > upper limbs > trunks (within 24 hours)
- acute, often self-resolving
EM → SJS → TEN
SJS/TEN
Term emergency (rare)
prodromal: flu-like
abrupt onset of lesions on trunk > face/limbs
macules, blisters, erythema = atypical features
blisters merge = sheets of skin detachment
Nikolsky +ve
extensive full thickness mucocutaneous necrosis <2-3 days
Hoe to describe term lesion
SJS/TEN
scale, crust and fissure
what is name for risk stratification score for pressure ulcers
Waterlow score
ulcer, scar, atrophy
keloid scar
hypertrophic scar
With hypertrophic scars, the extra connective tissue that forms within the original wound stays within that area. With keloid scars, the extra connective tissue that forms extends beyond the original wound area.
different types of scales
secondary skin changes
lichenification = seen in chronic dermatitis, thickened and shiny skin
Where on the body
acral = palms and soles of feet, distal extremities
blascho lines
A process in which injury to the skin causes further formation of psoriasis. (elbows and knees)
Shape descriptions
Colour descriptions
dilated or broken blood vessels located near the surface of the skin or mucous membranes.
Ddx sieve VITAMINE DEC
Ddx sieve VITAMINE DEC
Ddx of scale/papules/plaques
Herald patch
Ddx of blister
Ddx by site on body
Ddx by shape
SJS
Toxic epidermal necrolysis
Drug causes of SJS/TEN
If the test result is positive, the very thin top layer of skin will shear off, leaving skin pink and moist, and usually very tender. A positive result is usually a sign of a blistering skin condition. People with a positive sign have loose skin that slips free from the underlying layers when rubbed.
