Manifestations/Classification of Skin Diseases - Johnson Flashcards
functions of the skin
- protection and support of internal organs
- maintain homeostasis (temp, water and electrolyte balance)
melanocytes
- pigment cells to the skin
- 1/10 basal cells are melanocytes
pemphigus vulgaris
- autoimmune
- destruction of desmosomes (glue for squamous epithelial cells)
- keratinocytes separate
psoriasis
- immune mediated
- hyperproliferation of keratinocytes
- erythema, thick plaques
Piebaldism
- genetic –> autosomal dominant
- absence of melanocytes (failure of melanoblasts to migrate)
vitiligo
- autoimmune –> body attacks melanocytes
- associated with diabetes, thyroid, pernicious anemia –> damage other organs
most important prognostic indicator for melanoma?
breslow depth of lesion
recessive dystrophic epidermolysis bullosa
- defective basement membrane
- no place for epidermis to grow
scar tissue
- lacks hair and sweat glands
- damaged dermal/epidermal junction (basement membrane)
pseudoxanthoma elasticum
-elastic tissue defect –> wrinkles aka chicken neck
ground substance
- salt and water balance (bind water)
- viscosity for support
- promote growth, migration, differentiation
- defect –> mucopolysaccharidoses
Eccrine sweat gland
- secretory oil
- ducts open to surface
- temperature control
- hyper and anhidrosis
apocrine gland
- odiferous
- thermoregulation
- ducts open into hair follicle
diseases
- apocrine bromhidrosis –> smelly sweat
- hidradenitis suppurativa –> cysts, nodules, ulcers, fistulas
hair follicle growth cycle
- anagen –> active growing (ex. pregnancy)
- catagen –> transition
- telogen –> rest
diseases
- telogen effluvium –> hair shedding
- alopecia areata –> balding
sebaceous glands
- holocrine secretions**
- empty into hair follicle
- protective oil film
disease: acne
neurofibromatosis
-one of main neural skin diseases
flat primary lesions
- macule –> small flat
- patch –> large flat
- cannot feel
macule diseases
- Lentigines: Peutz-Jeghers –> brown macules; associated with chronic polyps
- Idiopathic Guttate Hypomelanosis –> white macules seen in elderly; no sun protection
patch disease
- cafe au lait: neurofibromatosis
2. vitiligo –> hypopigmented, irregular borders, satellite lesions
raised primary lesions
- papule –> small bump
- nodule –> larger bump
- plaque. –> raised; flat topped
- cyst –> deeper
- tumor –> larger nodule
papule diseases
- adenoma sebaceum: tuberous sclerosis –> hyperpigmented papules
- fixed urticaria/insect bites –> red, group like hives
- molluscum contangiosum –> flat top, umbilicate, viral
plaque diseases
- urticaria –> hive like; juicy feeling
2. psoriasis vulgaris –> deep, red scales
cyst diseases
- keratinous cyst
2. digital mucous cyst (translucent)
nodule diseases
- dermal: dermatofibroma –> fibrous dermis (scar tissue)
2. subcutaneous: rheumatoid nodule –> epidermis still intact
fluid filled primary lesions
- vesicle aka blisters –> small
- bulla –> large
- pustule –> cloudy, white/yellow fluid
herpes infection
- dew drops on a rose peddle
- red background
Dyshidrotic eczema
-abnormal sweating that leads to rash
bullous pemphigoid**
- where dermis meets the epidermis (deeper separation)
- tense bullae
pemphigus vulgaris**
- separation of desmosomes in epidermis (more superficial separation)
- flaccid bullae
purpuric primary lesions (small bruising)
- hemorrhage into skin or mucous membranes
- size and color variation
- no blanching with pressure (outside the vessel in the dermis)
ecchymosis
larger bruising
actinic purpura
- due to UV+steroids
- nonpalpable
non-palpable purpura
- Ecchymosis in amyloidosis
2. actinic purpura
non-palpable petechia
- RMSF
2. thrombocytopenia
palpable purpura
- leukocytoclastic vasculitis - common in legs; kidney problems, diarrhea, illness
- Henoch-schonlein purpura - IgA antibody
plaque, silvery scales on extensor surfaces?
psoriasis**
secondary lesions
Scaling/crusting Erosion Ulceration Excoriation Fissure Scar Hyper or Hypo -- Pigmentation
scaling lesions
- Guttate Psoriasis - from strep in the tonsils** (look like raindrops)
- tinea corporis - red, annular patch with some scaling
crusting
- impetigo
2. erythema multiforme - hemorrhagic crusting
atrophy
- epidermal atrophy - cigarette paper
2. dermal atrophy - inverse plaque, not juicy
erosion
- top part of epidermis is gone
1. herpes simplex in HIV
2. erodes bullous pemphigoid
ulceration
- infiltrating dermis below the basal membrane
1. Pyoderma Gangrenosum
2. Neuropathic ulceration in a diabetic
fissure
- When the epidermis is irritated - occurs when skin becomes dehydrated
1. irritant dermatitis
2. eczema craqule
eschar aka scab
- when cutting blood supply off from the skin
1. Eschar in lymphomatoid papulosis
2. Echthyma gangrenosum
limited distribution
Acral (Distal) Anogenital Scattered few Elbows and/or knees (Extensor surfaces) Flexural or Intertriginous areas Bite or trauma site Lymphangitic Dermatomal - ex. shingles Palmoplantar - ex. syphilus, hand-foot-mouth disease
extensive distribution
Widespread Primarily Truncal Extensor (arm, leg) - ex. atopic dermatitis Scattered Haphazard Symmetric Extremities Photodistributed - ex. sunburn Intertriginous - ex. jock itch Flexural
what affects children up to 1-2 years old and found on cheeks and extensor surfaces?**
-atopic dermatitis aka eczema**
varicella zoster virus
causes chickenpox and shingles
