Skin conditions (not infectious) Flashcards
Psoriasis pathophys
Chronic TH1 mediated cutaneous inflammation and hyperproliferation
TH1 cells produce cytokines IL2, TNFa, IL8 which attract and activate neutrophils
Histology of psoriasis
elongated rete redges
hyper and parakeratosis
neutrophils in epidermis
Auspitz
Clinical features of psoriasis
5 cardinal features: plaques, well circumscribed, bright salmon red colour, silevry micaceous scale, symmetric
extensor surfaces over bony prominences
nails: pitting, onycholysis, serous exudate, shedding, subungual hyperkeratosis
increased risk of cardiac events
Guttate psoriasis
acute extensive psoriatic papules over trunk and proximal extremities
usually associated with group A strep
Inverse psoriasis
flexural sites
lack scales
bright red, moist, macerated appearance
Pustular psoriasis
generalized pustular = fever, leukocytosis, life-threatening
localized - palms and soles
Erythrodermic psoriasis
entire body
red and scaly, prominent systemic complications
Dx psoriasis
clinical
Tx psoriasis
topical: GCs, tars, salicylic acid
phototherapy: UVB
Systemic (for recalcitrant disease): methotrexate, oral retinoids (acetretin), cyclosporine, biologics
Lichen planus pathophys
unknown
unrelated to any fungal/lichen infection
Lichen planus histology
dense band-like lymphocytic infiltrate at dermo-epidermal junction
basale destruction
hypergranulosis
hyperkeratosis
Lichen planus clinical features
5Ps: papule, pruritis, purple, polygonal, planar (flat-topped)
Wickman’s stria (whitish scale)
Oral mucosal lesions extremely common (lacy white lesions on buccal mucosa)
may be associated with Hep C
slow onset
Lichen planus Dx
clinical
Lichen planus Tx
1) topical steroid
2) topical retinoids
can use oral antihistamines to relieve severe itch
Pityriasis rosea pathophys
may be due to human herpesvirus infection; self-limit
Pityriasis rosea histology
parakeratosis, spongiosis
Pityriasis rosea clinical features
herald patch - solitary 2-6 cm scaly plaque
fine collarette scaling along rim of individual lesions
T shirt and shorts distribution
Mimicked by secondary syphilis (do VDRL) and drug eruptions
Pityriasis rosea Dx, Tx
clinical diagnosis
Tx usually not necessary
Eczema/atopic dermatitis pathophys
TH2 mediated cutaneous inflammation, possible S. aureus skin infection
impaired cutaneous barrier function
also allergic contact dermatitis, irritant contact dermatitis
Eczema histology
elonged rete ridges
hyper and parakeratosis
epidermal lymphocytes and Langerhans cells
spongiosis
Eczema clinical features
intense pruritis
not well-circumscribed
commonly secondary lesions seen due to rubbing (lichenification), excoriations
Eczema phases
infantile - facial and extensor
Childhood - flexural distribution, secondary lesions prominent
adult - improve gradually, may remit
Eczema tx
aggressive restoration of cutaneous permeability barrier (emollients, moisturizer)
1) topical GC
2) topical immunomodulators
oral antihistamines
Acne pathophysiology
inflammation of pilosebaceous units associated with formation of comedones
abnormal follicular keratinization, sebum overproduction, overgrowth of follicular bacteria (P. acnes)
Acne histology
neutrophil infiltration of pilosebaceous unit
plugging of hair follicle with keratin
fibroblastic and collagen proliferation in normal derma structures
Acne clinical features
most commonly found in areas of the most sebaceous secretion (face, shoulders, upper back, upper chest) closed comodones (white heads) and open comedones (black heads) - closed comedones more likely to give rise to inflammatory lesions
Mild acne
mostly comedones, few inflammatory lesions, no scars
Moderate acne
comedones, papules and pustules, no deep cysts or nodules
Severe acne
cysts or nodules, significant scarring
Acne tx
1) gentle cleansing BID
2) retinoic acid, antibiotics, benzoyl peroxide, salicylic acid
oral: systemic isoretinoin (retinoic acid)
antibiotics (relapse is common)
Rosacea pathophys
unknown
papulopustular components centred on the pilosebaceous unit
but underlying abnormalities are vascular, not follicular in origin
Rosacea histology
inflammatory periadnexal infiltrates
occasional parasitic infestations of follicles (Demodex)
sebaceous hyperplasia
Rosacea clinical features
commonly middle-aged type 1: Erythematotelangiectatic rosacea 2: papulopustular rosacea 3: phymatous rosacea (develop rhinophyma 4: ocular rosacea (conjunctivitis, blephoritis, iritis, keratitis)
Rosacea dx
clinical
DDx acne vulgaris
Tx rosacea
avoid triggers - sun, heat, alcohol
laser ablation for telangiectasia
tetracyclines and cold compress for erythema
metronidazole, azaleic acid, systemic antibiotics for papulopustular
systemic tetracyclines and isotretinoin = moderately effective for phymatous rosacea
Pemphigus pathophys
rare antibody-mediated vs antigen important in allowing keratinocytes to adhere (intraepidermal split)
fluid accumulates in intraepidermal split - clinically apparent fragile bullae
Pemphigus histology
suprabasal intraepidermal cleft
Pemphigus clinical features
easily ruptured bullae
flaccid erosions common
Pemphigus tx
topical/systemic steroids
immunosuppressives (methotrexate)
Bullous pemphigoid pathophys
antibodies to antigens in basement membrane zone between epidermis and dermis
Bullous pemphigoid histology
inflammatory infiltrate of eosinophils near dermo-epidermal junction
subepidermal split
full thickness of epidermis above fluid accumulation
Bullous pemphigoid histology clinical features
pruritic erythematous plaques tense bullae (not fragile) with few erosions
Bullous pemphigoid treatment
better prognosis than pemphigus vulgaris
prednisone; IVIG or rituximab if refractory
Drug eruptions pathophys
undesirable response to medication at a certain dose
Drug eruption clinical features
urticaria
maculopapular/morbilliform (measles-like)
localized inflamed plaques that recur at same body site each time patient is exposed
Exacerbating factors for psoriasis
Koebner phenomenon Infections (GAS, HIV) dry air/skin stress alcohol and drugs - flareup after discontinuation of prednisone - lithium, beta blockers - any cutaneous drug eruption
Ameliorating factors for psoriasis
sunbathing (UVB immunosuppression)
moisturizes
Pregnancy - benign skin changes
Striae gravidarum
Hyperpigmentation at areola, axillae and genitals
increase or decrease in growth and production of hair
nails usually grow faster
vascular changes - spider telangiectasias, palmar erythema, saphenous, vulvar, or hemorrhoidal varicosities
Preexisting skin conditions may change
Atopic dermatitis/psoriasis may worsen or improve; psoriasis more likely to improve
Fungal infections generally require longer treatment course during pregnancy
PUPPP
Pruritic urticarial papules and plaques of pregnancy
- intense pruritis, develops in the 3rd trimester and generally first appears on abdomen often along striae and occasionally involves extremities
face spared
Prurigo of pregnancy
erythematous papules and nodules on extensor surfaces of extremities
INtrahepatic cholestasis of pregnancy
intrahepatic cholestasis occurring in the 3rd trimester
results in excoriation from scratching with non-specific distribution
Pemphigoid gestationis
AI skin disorder in mid to late term pregnancies with linkage to HLA-DR3 and DR4
can take variable course although it generally improves in late pregnancy with exacerbations in the immediate postpartum period
pruritic papules, plaques and vesicles evolving into generalized vesicles or bullae
Initial periumbilical lesions may generalize although face, scalp and mucous membranes usually spread
Impetigo herpetiformis
pustular psoriasis that is a rare skin disorder in the 2nd half of pregnancy
round, arched or polycyclic patches covered with small painful pustules in a herpetiform pattern
most commonly appears on thighs and groin but rash may coalesce and spread to trunk and extremities
face, hands and feet are spared but mucous membranes may be involved
Pruritic folliculitis of pregnancy
occur in 2nd and 3rd trimester and present as erythematous follicular papules and sterile pustules on abdomen, arms, chest and back
CONTRARY TO ITS NAME purities is not a major feature
