1.2 Pathology of Skin (pt 2) Flashcards
how does seborrheic dermatitis present microscopically
spongiotic dermatits & acanthosis w/ parakeratotic mounds around the hair follicles (“follicular lipping”) & mixed inflam population
what is pemphigus vulgaris
most common
-mucosa & skin (esp scalp); may present in oral ulcers
lesion = superficial vesicle & bullae rupture easily = suprabasalar blister - part of epidermis (including stratum corneum)
what is hereditary angioneurotic edema?
inherited deficiency of C1 inhibitor –> excess activation of early components of complement & produce vasoactive mediators
worry about this when angioedema present (which is related to utricaria but has edema in deeper dermine & subQ fat)
what is an example of disorders of epidermal maturation
ichthyosis
What is erythema multiforme associated with?
(=the self-limited hypersensitivity rxn)
- infxns (viral, bacterial and fungal) *HSV & mycoplasma & histoplasma & coccidiomycosis*
- drugs (sulfa, penicillin, barbiturates, salicylates, antimalarial, hydantoins)
- cancer
- collagen vascular dz (SLE, dermatomytosis & polyarteritis nodosa)
what is epidermolysis bullosa
=non-inflam
= group of disorders due to inherited defects in structural protein that provide mechanical stability (keratin)
commonly: form blistes at sides of pressure, rubbing or trauma or at/soon after birth
so subtle that electron microscopy may be required to differentiate btn types
What are examples of panniculitis
(define panniculitis)
erythema nodosum
erythema induratum
=inflam of subQ layer of fat (deep & nodular)
What is seborrheic dermatitis? what is it correlated w/?
= chronic inflam, more common than psoriasis
involves regions w/ high density of sebaceous glands (scalp, forehead, external auditory canal, retroauricular area, nasolabial folds and presternal areas)
BUT** rmr **NOT a dz of glands it self
correlations = HIV w/ low CD4 count & parkinsons
what are examples of epidermal appendages
acne vulgaris
rosacea
describe ichthyosis & its morphology
inherited disorder - seen at or soon after birth
=disorder of epidermal maturation ==> hyperkeratosis –> fishlike scales
morphology: build up of compacted stratum cornem ; defective desquamation –> retention of abnormal formed scale
some variants = paraneoplastic of lymphoid or visceral malignancy (esp GI tract)
how long do acute inflam lesions last?
what are they characterized by?
days - weeks
=characterize by inflam inflitrates (lymphocytes, macrophages), edema, degree of epidermal, vascular or subcutaneous injury
what are characterisics of the bacteria is causing proprionibacterium acne
what has it been recently associated with?
“Acutibacterium” - proprionibacterium (gram +) - prefer anaerobic
= actinobacteria
associated w/ chronic blepharitis & endophthalmitis (after intraocular surgery) & prosthetic related infxn, & chronic nerve root inflam
What is pemphigus foliaceus
blister found in superficial epidermis at level of stratum granulosum
subcorneal blister - stratum corneum forms roof of bulla
what is verruca vulgaris?
what is the pathogenesis/morphology
common warts (esp kids)
pathogenesis: HPV
morphology: verrucous/papillomatous epidermal hyperplasia ; koilocytosis (cytoplasmic alterations) = (pic C)
treatment with _____ & ____ have shown efficacy for psoriaris w/ auspitz sign
anti-TNF & anti- IL 17
how does erythema multiforme present?
macules, papules, vesicles & bullae
cutaneous & mucucutaneous “target” lesion - face & extremities
what is lichen planus?
How does it present (acute & chronic)
6 P’s: Pruritis, Purple, Polygonal, Planar, Plaque, Papules
disorder of the skin & mucosa
=self limited (resolve w/i 1-2 yrs) - resolution will leave residuum of post-inflam hyperpigmentation & oral lesions may persist for years
SCC occur in chronic mucosal & paramucosal lesions
Koebner phenomenon (like psoriasis)
Wickham striae: white dots/lines that highlight the papule
How does dematitis herpetiformis present?
whats the pathogenesis/morphology behind it?
= urticaria & grouped vesicles; plaques and vesicles are extremely pruritic
M>F, 30s-40s
pathogenesis: *association w/ intestinal celiac dz* - responds to gluten free diet
Ab cross react w/ reticulin –> subepidermal blister
morphology: IgA granular deposits - localize in the tips of dermal papillae
what is the difference in action of mast cells in acute vs chronic response
acute: IgE Ab bind to Fc receptor –> cell degranulate and release mediators (histamine and prostoglandins)
chronic: secrete cytokines and promote inflam rxn
What are examples of chronic inflam dermatoses
psoriasis
seborrheic dermatitis
lechin planus
what are causes for acne
*rmr: Whitehead = open & blackhead = closed*
hormonal fluctuation, androgens
obstructive effects
chronic inflam
proprionibacterium (reason why antibiotics can be use to treat acne!)
What are the different levels w/i the skin that blisters can develop
- Subcorneal: stratum corneum from roof of bulla (under stratum corneum) pemphigus foliaceus
- Suprabasal: portion of epidermis, including stratum corneum, form roof (right above basalar layer) pemphigus vulgaris
- Subepidermal : entire epidermis and dermis separate bullous pephigoid
what are examples of derm infections
verracae
molluscum contagiosum
impetigo
superficial fungal infxn
what are examples of acute inflam dermatoses
urticaria
acute eczematous dermatitis
erythema multiform
what is the pathogenesis and morphology for acute eczematous dermatitis?
pathogenesis: Type IV hypersensitivity
morphology: red, papulovesicular (blister), oozing –> if persistent - reactive acanthosis and hyperkeratosis make raised plaques
(lesions are prone to bacterial superinfxn –> yellow crust (impetiginization))
=characterized by “epidermal spongiosis” -edema in intercel space - prominent seperation btn keratinocytes (esp stratus spinosum)
What type of panniculitis tends to affect teen & menopausal women
describe the disorder
erythema induratum
-possible primary vasculitis of deep vessels supplying fat lobules of subQ skin
erythematous nodules –> ulcerate
what is acantholysis
splaying apart keratinocytes due to spongiosis
what derm disorder is associated w/ increased/abnormal endogenous anti-microbial proteins & activation certain mediates like toll-like receptors?
Rosacea
(i. e catheliciden peptide)
- face (cheek, nasolabial fold)
chronic inflam
Spectrum = persistent erythema <–> pustules <–> development of rhinophyma (ENLARGED NOSE)
What is the morphology of Lichen Planus?
wickham stria
= pink-purple, polygonal papule w/ white lacelike pattern
- has bandlike infiltrate of lymphocytes at dermoepidermal jxn, hyperkeratosis and pointed rete (sawtooth)
what is psoriasis and what other conditions is it associated w/
= chronic inflam dermatosis that appears to have autimmune basis (see in all ages)
-associated w/
- arthritis (15%)- may be mild or produce deformities resembling RA (one side or symmetric)
- myopathy
- enteropathy
- AIDS
What is the pathogenesis & morphology for psoriasis
pathogenesis: sensitized CD4, Th17 and activated CD8; driven by Th1 & Th17 (IL 12, IL 17, INF-gamma & TNF) ; 2/3 pt = HLA-C gene
Koebner phenomenon: areas w/ trauma have psoriatic lesions bc motion for local inflam which becomes self-perpetuating
morphology:
- nail changes
- stratum granulosum thinned/absent
- biopsy show: change in papilary dermis, acanthosis, scaling, microabsess in stratum corneum
- Auspitz Sign - dilated vessels of underlying dermal papillae - multiple, minue and bleeding point
What is pemphigus vegetans
large, moist, wart-like vegetating plaque studded w/ pustules
cells immediately above basal layer
overlying epidermal hyperplasia
what are the 5 types of pemphigus
vulgaris
vegetans
foliaceous
erythematosus
paraneoplastic
What is the pathogenesis and morphology of impetigo
= common superficial bacterial infxn (usually due to Staph aureus)
pathogenesis: innate immune response –> epidermal injury –> local serous exudate & form scab
& blister formation = bacterial production that cleaves desmoglein 1 (responsible for cell-cell adhesion in upper most epidermal layers)
morphology: erythematous macules that progress to small pustules –> to shallow erosions covered w/ drying serum as pustules (honey colored crust)
accumulation of neutrophils beneath stratum corneum
What is bullous pemphigoid
subepidermal, nonacantholytic blister
elderly pts
-inner thigh, flexor surfaces - forearm, axillae, groin and lower abdomen
oral lesion (10-15%)
possible utricarial plaques w/ severe pruritus
auto-ab IgG - bind to proteins required for adherence of basal keratinocytes to BM (hemidesmosomes)
What are toxic epidermal necrolysis & steven johnson syndrome
=severe epidermolytic adverse cutaneous drug rxns (skin & mucous membrane)
- rare; medical emergencies!
=mucocutaneous tenderness & hemorrhagic erosions, erythema and more/less severe epidermal detachment - presenting as blisters & ares of denuded skins
differ by extend of skin detachment
what is pemphigus erythematosus
localized
may have selective malar presentation like SLE
what are characterisitics and examples of superficial fungal infxns
confined in stratum corneum
caused by dermatophytes from soil or animal
= bright pink/red w/ PAS & are found in anucleated cornified layers of lesional skin, hair or nails
What is Molluscum Contagiousm
- self limited viral skin dz (children & young adults)
morphology: umbilicated pink papules; molluscum bodies - large ellipsoid, homogenous, cytoplasmic inclusions in cells of stratum granulosum & corneum
what are the subdivisions of acute aczematous dermatitis?
- allergic contact
- atropic
- drug-related
- photoeczematous
- primary irritant
What is the NODOSUM mneumonic for erythemal nodosum
NO cause found in 60% cases = idopathic
Drugs (sulfa, antibiotics, etc)
Oral contraceptives
Sarcoidosis or Lofgren’s syndrome
UC, crohns, bechets
Micro: (infxns - TB, EBV, HSV, camplobacter, syphilis, etc)
= nodular & painful = septal panniculitis
what is paraneoplastic pemphigus
associated w/ malignancies (most common NHL)
Auto-Ab that recognize desmogleins or other proteins of intercellular adhesion
what is the immune mechanism, histopathologic lesions of type I (immediate) hypersensitivity
(when do these rxns occur?)
=make IgE Ab -> release vasoactive amines from mast cells & later recruit inflam cells
histopath lesions: vascular dilation, edema, Sm M contraction, mucous production, tissue injury & inflam
(anaphylaxis, allergies, bronchial asthma)
what is pemphigus caused by
IgG auto-Abs against desmogleins- result in dissolution of intercellular attachment w/i epidermis & mucosal epithelium
5 types
What is Weber-Christian Dz
relapsing febrile nodular panniculitis
how does psoriasis present?
on elbows, knees, scalp, lumbosacral areas, intergluteal cleft & glans penis
=pink to salmon colored plaque covered by loosely adherent silver-white scale
possible nail changes- yellow-brown discoloration w/ pitting, dimpling, separation of nail plate (onycholysis) , thickening, crumbling
what are examples of blistering (bullous) dzs
inflam
- pemphigus
- bullous pemphigoid
- dermatitis herpetiforms
Noninflam
- epidermolysis bullous and porphyria
What are porphyrias
= noninflam
=group of uncommon inborn/acquired distrubances of porphyrin metabolism
*porphyrin - pigments in Hb, myoglobin and cytochromes
bone and skin involvement - urticaria & vesicles associated w/ scarring (worse w/ sunlight)
if a pt presents w/ firm edematous plaques that last only a few hrs..
what do they have?
describe the morphology
Utricaria (wheals - hives)
firm edematous plaque resulting from infiltration of dermis w/ fluid
type I hypersensitivity ==> localized mast cell degranulation –> dermal microvascular hyperpermeability
compare w/ angioedema - which is edema of deeper dermis & subQ fat
morphology: sparse mononuclear infiltrate & occasional dermal eosinophils
what are chronic inflam lesions characterized as
month- years
= epidermal changes (atrophy/hyperplasia) &/or dermal fibrosis
