Skin pathology: Inflammatory dermatoses Flashcards
function of skin
barrier against environmental insults and fluid loss
what composes the skin
epidermis and dermis
Epidermis has what in it, and what are the layers
keratinocytes
- statum basalis
- stratum spinosum
- stratum granulosum
- statum corneum
characterize Stratum basalis
regenerative (stem cell) layer
characterize Stratum spinosum
desmosomes between keratinocytes
characterize Stratum granulosum
granules in keratinocytes
characterize Stratum corneum
keratin in anucleate cells
what is located in the dermis
connective tissue
nerve endings
blood and lymphatic vessels
adnexal structures
what are adnexal structures
hair shafts
sweat glands
sebaceous glands
What is atopic (eczematous dermatitis)
pruritic, erythematous, oozing rash with vesicles and edema
where does atopic (eczematous) dermatitis usually occur
face and flexor surfaces
what type of hypersensitivity is atopic (eczematous) dermatitis
Type I hypersensitivity
what is atopic (eczematous) dermatitis associated with
asthma
allergic rhinitis
what is conact dermatitis
pruritic, erythematous, oozing rash with vesicles and edema
what can cause contact dermatitis
exposure to allergens:
- Poison Ivy and Nickel Jewelry ( type IV)
- irritant chemicals (e.g., detergents)
- drugs (e.g., penicillin)
how is contact dermatitis treated
- removal of offending agent
- topical glucocorticoids, if needed
what is acne vulgaris
- comedones (whiteheads and blackheads)
- pustules ( pimples)
- nodules
who usually gets acne vulgaris
extremely common
-especially adolescents
what causes acne vulgaris
chronic inflammation of hair follicles and associated sebaceous glands
what are 2 causes of acne vulgaris
- hormone-associated
2. Propionibacterium acnes
Propionibacterium acne causes acne how?
- produces lipases that break down sebum
- releasing proinflammatory fatty acids
- results in pustule or nodule formation
how does hormone -associated acne vulgaris cause acne
- increases in sebum production: sebaceous glands have androgen receptors
- excess keratin production: blocks follicles
forming comedones
What is the treatment for acne vulgaris
- Benzoyl peroxide ( antimicrobial)
- vitamin A derivatives ( isotretinoin) - reduces keratin production
what is psoriasis
well-circumscribed, salmon-colored plaques with silvery scale
where does psoriasis usually occur
extensor surfaces and saclp
what is physical exam finding for psoriasis
pitting of nails
what causes psoriasis
excessive keratinocyte proliferation
what are 2 etiologies of psoriasis
- associated with HLA-C
2. Lesions often arise in areas of trauma ( environmental trigger)
Name 4 things that show up in histo fo psoriasis
- acanthosis
- Parakeratosis
- Munro microabscesses
- thinning of epidermis above elongated dermal papillae
acanthosis
epidermal hyperplasia
parakeratosis
hyperkeratosis with retention of keratinocyte nuclei in stratum corneum
munro microabscesses
collections of neutrophils in stratum corneum
what is Auspitz sign
thinning of epidermis –> bleeding when scale is picked off
-psoriasis
treatment for psoriasis
corticosteroids
UV light with psoralen
immune-modulating therapy
what is lichen planus
pruritic, planar, polygonal, purple papules, often with reticular white lines on their surface ( Wickham striae)
common location of lichen planus
wrists, elbows, oral mucosa
oral involvement for lichen planus manifests as
Wichman striae
etiology of lichen planus
unknown
- associated with chronic Hep C virus infection
What is pemphigus vulgaris
autoimmune destruction of desmosomes between keratinocytes
what causes pemphigus vulgaris
IgG antibody against desmoglein
Type II hypersensitivity
how does pemphigus vulgaris present on the skin
skin and oral mucosa bullae
what is the histo for pemphigus vulgaris
- acantholysis (separation) of stratum spinosum keratinocytes ( normally connected by desmosomes) –> suprabasal blisters
- basal layer of cells remain attached to basement membrane via hemidesmosomes (‘tombstone’ appearance)
what is Nikolsky sign for pemphigus vulgaris
thin-walled bullae rupture easily
-leading to shallow erosions with dried crust
