Diseases Flashcards
allergic contact dermatitis (ACD)
type IV delayed hypersensitivity: T cell mediated
Sx: pruritus
rash: eczematous, scaly edematous plaques with vesicles in area of exposure
Hx: daily skin care routine, all topical products, occupation/hobbies, regular and occasional exposure (lawn care products, animal shampoos)
Tx: avoid exposure
irritant contact dermatitis (ICD)
inflammatory reaction in skin resulting from exposure that can cause an eruption in most people (non-immunologic)
host and environmental elements
NO previous exposure necessary
single application with severely toxic substance or repeated application of mildly irritating substances (soap, detergent)
sites: thinner skin: face, neck, scrotum, dorsal hands
risk factor: atopic dermatitis
Sx: erythema, chapped skin, dry, fissuring, pruritus, pain
severe Sx: edema, exudate, tender, bull within hours
Tx: avoid irritant, topical steroids, emollients to improve barrier
prevention: protective equipment, avoidance
need patch test in occupational cases to exclude allergic contact dermatitis
atopic dermatitis (AD)
before age 5, clears by adolescence
loss of FILAGGRIN: Th2 immunity
mutlifactorial: genetics, skin barrier dysfunction, impaired immune response, environment
type I hypersensitivity triad: allergic rhinitis, bronchial asthma, AD
chronic, pruritic, inflammatory skin disease
Sx: pruritus, xerosis
ITCH that RASHES: erythematous papules that coalesce to plaques with weeping, crusting, or scaling
Tx: avoid trigger, anti-inflammatory therapy, skin care to compensate for genetically determined impaired barrier, emollients (petrolatum), topical steroids, tacrolimus, pimecrolimus, oral steroids, phototherapy in refractive cases, oral antibiotics if infected with staph
dyshidrotic dermatits
firm vesicles of the palms, soles, lateral and medial fingers and toes
Sx: pruritus, burning, prickling sensation
associations: atopic dermatitis, contact dermatitis
NO disturbance of sweat gland function
may be related to stress, atopy, allergens (topical and ingested)
Tx: steroids (topical and systemic), topical calcineurin inhibitors, consider underlying allergen/irritant
Lichen simplex chronicus
chronic, intensely pruritic skin condition triggered by repeated rubbing and scratching
Sx: solitary, well-defined, pink to tan, thick and lichenified plaque
locations: lateral neck, scrotum/vulva, and dorsal foot
Tx: topical steroids and break habit of scratching
acute dermatitis
appears vesicular or bullous
chronic dermatitis
red, scaly and lichenified with fissures
pruritus
itching
common in all types of dermatitis
causes of contact dermatitis
most common: Rhus dermatitis: poinson ivy, oak, sumac (all contain urushiol)
other: nickel, rubber, fragrance, preservatives, formaldehyde, topical antibiotics, benzocaine, Vitamin E
What are the two phases of allergic contact dermatitis?
- sensitization (induction): 10-14 days
2. elicitation (challenge): dermatitis within 12-48 hours
Rhus allerg
allergic contact dermatitis: poison ivy, sumac, oak
initial episode: rash 7-10 days after exposure
duration: up to 6 weeks
other episodes: within 2 days
duration: 10-21 days
Tx: topical steroids, antihistamine, oatmeal soak/ calamine lotion
severe: oral steroids for 2-3 weeks
prevention: avoid plants, wash objects exposed, apply barriers
eyelid allergic contact dermatitis
causes: often from transfer from hands: nail polish, cosmetics, nickel
Sx: intensely pruritic
scaling red plaques greater on upper lids
patch testing
determines which allergens a patient with allergic contact dermatitis reacts against
use ONLY when allergen is unclear
apply to back, remove in 2 days
latex allergy (2 types)
delayed hypersensitivity: allergic contact dermatitis on dorsal surface of hands
immediate hypersensitivity: immediate burning, stinging, itching with or without localized urticaria, may include disseminated urticaria, allergic rhinitis, anaphylaxis
location of atopic dermatitis lesions by age
- infants and toddlers: eczematous plaques on cheeks, foreheads, scalp, extensor surfaces
- older children, adolescents: lichenified eczematous plaques in flexural areas of neck, elbows, wrists, ankles
- adults: lichenification in flexural regions and involvement of hands, wrists, ankles, feet, face (forehead and around eyes)
eczema herpeticum
severe herpes simplex virus infection in atopic dermatitis patient
severe cases require hospitalization
Tx: IV acyclovir
nummular dermatitis/ discoid eczema
older
coin shaped, well demarcated plaques with scales and tiny vesicles
location: legs, dorsal hands, extensor surfaces
Sx: intensely pruritic, worse in winter (DRY SKIN)
Tx: topical steroids, topical tacrolimus or pimecrolimus, emollients, phototherapy
may be linked to impaired skin barrier function
urticaria
rapid development of hives: evanescent, itchy swellings of skin
wheals last few hours before resolving, may have angioedema up to 72 hrs
*consider urticarial vasculitis if wheals last longer than > 24 hrs
HISTAMINE release and other cytokines: edema
can be allergic or non-allergic, with or with our identifiable cause
Prevent: antihistamines, leukotriene antagonists, H2 blockers
usually avoid steroids: risk of rebound
causes of urticaria
acute ( 6 weeks): unknown, chronic infection, rheumatologic disorder, Ab to IgE
angioedema
swelling of deep dermis and subcutaneous tissue
more frequent with food induced urticaria
typically face: lips, periorbital, hands, feet
also: tongue larynx, respiratory, GI: can cause anaphylaxis (wheezing, difficulty breathing, abdominal pain, dizzy, low BP)
hereditary angioedema
C1 inhibitor deficiency
recurrent episodes of edema, abdominal pain
angioedema without urticaria
often drug therapy related
angiotensin-converting enzyme inhibitors
physical urticarias
not immunologic; physical cause
dermatographism, cold/heat ,delayed pressure , solar, aquagenic, cholinergic
cutaneous drug reactions
risk: increased age, female, concomitant viral infection (HIV, EBV)
common causes: antibiotics, anticonvulsants, NSAIDS
rash: morbilliform (maculopapular) or urticarial
morbilliform drug reaction
type-IV hypersensitivity: cell-mediatedmorbilliform
MOST common
5-7 days after starting drug (even few days after drugs is discontinued)
penicillins, cephalosporins, sulfonamides
anticonvulsants
Tx: resolve spontaneously in one to two weeks
urticarial drug reactions
immediate hypersensitivity: IgE mediated requires prior exposure penicillins, cephalosporins aspirin latex
drug rash with eosinophilia and systemic systems (DRESS)
drug hypersensitivity syndrome
severe morbillifrom drug reaction with eosinophilia and systemic illness
onset: 2-6 weeks after exposure, facial edema, fever, lymphadenopathy, joint pain, liver
persists weeks to months after drug is stopped
cause: anticonvulsants, antibiotics (sulfonamides, minocycline, erythromycin)
Tx: long term with corticosteroids
mortality: 10% from fulminant hepatitis
fixed drug eruption
well circumscribed, red brown plaque, may blister heals with hyper pigmentation same location with repeated exposure location: genitals, lips, extremities causes: sulfonamides, NSAIDS, laxatives
stevens-johnson syndrome/toxic epidermal necrolysis
life-threatening blistering skin and MUCOUS membranes
onset: 1-2 mo. starting drug
Sx: flu like, mucosal irritation, conjunctivitis, dysuria
rash: starts morbillifrom or dusky target lesions, painful or burning; skin peels full thickness
multisystem involvement
Tx: remove drug, supportive care in burn unit, IV immunoglobulin
high mortality
steroids increase mortality
drugs associated with stevens-johnson syndrome
antibiotics: sulfonamides, penicillins, cephalosporin
anticonvulsants: phenobarbital, carbamazepine, lamotrigine
allopurinol, NSAIDS (oxican derivatives), nevirapine, abacavir, acetaminophen in children
What is the difference between stevens-johnson syndrome and toxic epidermal necrolysis?
less than 10% body area: SJS
10-15%: overlap
greater than 15%: TEN
bullous pemphigoid
female, old
Ab to HEMIDESMOSOMES
target antigens: BP 180/230
Sx: very itchy urticarial rash, tense blisters (usually symmetric distribution) with/out surrounding erythema, mucous membrane involvement in a few
DIF: solid line with IgG and C3 at dermal-epidermal junction
Dx: skin biopsy for DIF
may or may not find Ab in blood
Tx: systemic steroids, immunosuppressants
pemphigus vulgaris
50-60 yrs, men
Mediterranean, Ashkenazi Jew
Ab to DESMOSOMES
target antigen: desmoglein 1/3
Sx: erosion in mouth, painful erosions, if have blisters they break easy
location: head, chest, back, intertriginous areas (armpit, groin), extensive membrane involvement (mucosa, larynx, esophagus, conjunctiva)
Dx: skin biopsy: DIF; serum Ab
Tx: steroids, immunosuppressants, Rituximab
high fatality without Tx
dermatitis herpetiformis
men, 30-40 autoimmune CELIAC disease: enteric GLUTEN sensitivity EPIDERMAL TRANSGLUTAMINASE IgA Ab to e-TG Sx: GI, intensely itchy (may see blisters) location: elbow, butt, knee, scalp, neck Tx: gluten free diet, dapsone for itch complication: lymphoma
hemidesmosome
attach epidermis to BM
BULLOUS PEMPHIGOID
mucous membrane pemphigoid
Ab to hemidesmosomes
scarring eye involvement, can lead to blindness; oral lesions
with/out skin lesions
gestational pemphigoid (herpes gestationis)
Ab to hemidesmosomes
bullous pemphigoid in pregnant women (2nd trimester), can reoccur with successive pregnancies or oral contraceptives
associated with preterm labor or low weight for gestational age
regresses post partum
pemphigus foliaceus
superficial pemphigus
Brazil
Ab to desmoglein 1
Sx: scale crust resembles corn flakes
paraneoplastic pemphigus
pemphigus associated with malignancy
sever and recalcitrant mucosal involvement
tissue transglutaminase (t-TG)
CELIAC
cross reacts with epidermal transglutaminase (e-TG)
transglutaminases
cytoplasmic Ca dependent enzymes that catalyze crosslinks between glutamine and lysine
important in forming insoluble protein polymers: blood clots hair, skin
BP 180 or BP 230
BULLOUS PEMPHIGOID
desmosomes
attach keratinocytes to one another
PEMPHIGUS VULGARIS
desmoglein 1 and 3
PEMPHIGUS VULGARIS
epidermal transglutaminase (e-TG)
DERMATITIS HERPETIFORMIS
purpura
non-blanchable, pink to purple macules/patches or papule causes by extravasated RBCs in skin or mucus membranes
blood under skin (press and don’t blanche)
causes: coagulation/clotting abnormalities, leaky or abnormal vessels, trauma
macular/non-palpable purpura
generally non-inflammatory
palpable purpura
sign of vasculitis
petechiae
non-palapable purpura
small,
ecchymosis
non-palpable purpura
larger area of purpura > 5 mm
may be painful or tender
abnormalities in COAGULATION: hyper or hypo
multifactorial causes of purpura
- thrombocytopenia and infection/trauma/inflammation
- abnormal platelet and infection/trauma/inflammation
- infection
- anticoagulant and trauma (DIC, renal/hepatic dysfunction,Vit. K deficiency, anticoagulation drugs)
- poor dermal support and trauma (actinic damage, amyloid, steroid atrophy, scurvy, fragility syndromes)
palpable purpura
associated with inflammation in blood vessels
hallmark of leukocytoclastic vasculitis
vasculitis
affects skin primarily and visibly
can effect: kidneys, lungs, CNS, GI
small vessel vasculitis
palpable purpura, blisters, less commonly hives
Henoch Schonlein purpura (IgA)
infection, drug reaction, autoimmune, malignancy related. idiopathic, hypersensitivity
small/medium vessel vasculitis
ANCA associated: Churg-strauss, microscopic polyangiitis, Wegner’s granulomatosis
Cryoglobulinemic vasculitis
medium vessel vasculitis
nodules, purpura, livedo reticularis/racemosa
polyarteritis nodosa
large vessel vasculitis
less likely to affect skin
Giant cell arteritis, Takayasu arteritis, Behcet’s
retiform purpura
NETLIKE pattern of ecchymosis
results from vascular ischemia due to underlying thrombotic disorder (acquired or congenital)
ill patient with fever with retiform purpura: INFECTION (meningococcemia is most worrisome)
purpura fulminans
widespread retiform purpura
psoriasis
20s, 50s
T cell mediated
familial
mucosal changes, geographic tongue
NAIL disease: oil spots, nail pitting, distal onycholysis, subungual debris
risk of: arthritis, obesity, DM, hyperlipidemia, HTN, CV disease
flares associated with: group A strep, drugs, stress
Tx: phototherapy, TNFa inhibitors, IL12/23 blocker, IL-17 blocker
topical: steorids, retinoids, vit. D, topical keratolytics, tar
NOT systemic steroids: risk of flare with discontinuing
seborrheic dermatitis
inflammatory rxn to MALASSEZIA (Pityrosporum ovale) yeast that thrives on old producing skin: sebum production
erythematous or hypopigmented greasy scaling patches on scalp, hairline, eyebrows, eyelids, central face, nasolabial folds, external auditory canal or central chest
worse in HIV
Tx: low potency topical steroids, topical ketoconazole, topical pimecrolimus, antidandruff shampoo (ketoconazole, selenium sulfide, zinc pyrithione)
pityriasis rosea
young 10-35 yrs
HHV6/7 possible
salmon, purple, brown or gray: herald patch first, second CHRISTMAS TREE trunk and extremities (follow tension lines)
Sx: none or flu-like
Tx: resolves on own in 5-8 wks
if it itches: OTC anti-itch lotion, topical steroid, antihistamine, oral erythromycin
Lichen planus
middle-age
autoimmune rxn to antigens on lesional keratinocytes
idiopathic inflammatory disease of skin, hair, nails, mucous membranes
pruritic, purple, polygonal, flat topped papule with reticulated network of white lines (Wickham’s striae)
lesions koebnerize: FLEXOR wrists, forearms, dorsal hands, lower legs, pre sacral area, neck glans penis
associations: HEP C
Tx: topical/ intralesional corticosteroids
plaque type psoriasis
MOST COMMON
well demarcated, erythematous plaques with adherent silver to while scale
scalp, extensor surfaces of extremities, periumbilical and sacral trunk
guttate type psoriasis
second most common
young adults
multiple small drop shaped erythematous scaly plaques diffusely on body: mostly trunk
often preceded by streptococcal infections (PHARYNGITIS)
Tx: antibiotics if caused by strep
pustular type psoriasis
superficial pustules localized on palm and soles or general
inverse psoriasis
intertriginous areas
erythrodermic psoriasis
diffuse erythroderma with fine scaling
Koebner phenomenon
psoriasis at sites of trauma
cradle cap
infantile seborrheic dermatitis
pink to yellow macule and patches with white greasy scales on scalp, face, diaper area
inverse pityriasis rosea
confine to groin and axilla
lichen planopilaris
follicular variant of lichen plans that causes scarring alopecia
lichen planus clinical variants
- annular
- bullous
- hypertrophic
- inverse
- linear
- ulcerative
- vulvovaginal-gingival
- drug induced
- lichen planopilaris
difficult to treat mucosal; hypertrophic needs high potency under occlusion or intralesional steroids
drug induced lichen planus
photodistribution or indistinguishable from idiopathic
drugs: ACE inhibitors, thiazides, antimalarials, quinidine, gold
sarcoptes scabiei (scabies)
direct contact or fomites
infestation to Sx: 3-4 wks (re-infestation only 1-2 days)
location: axillae, breasts, umbilicus, penis, scrotum, finger webs, wrists
head and scalp in infants, elderly, immunocompromised
Dx: skin scraping (mineral oil prep)
Sx: itching at NIGHT
Tx: two topical tx one week apart with Rx (permethrin cream, precipitated sulfur, oral ivermectin) neck down and leave overnight (include face and scalp for infants and elderly)
itch/lesions can persist for 2-4 wks after Tx
environment: wash clothing and linens, high heat dry, seal others in bad 3 days
pediculosis (lice)
school age (any socioeconomic), less in AA
live eggs remain close to scalp (1cm): can estimate duration
spread: close contact, fomites
viable egg: tan/brown
hatched: white
Sx: itching, posterior cervical LAD, dermatitis at posterior neck
Dx: nits/lice (more likely to see nits, lice scurry away from light)
Tx: topical permethrin, re-treat in 7-9 days to kill newly hatched, nit comb
resistant: malathion
other: examine/treat household, wash bedding, clothing and dry on hot, brushes hot water for 10 min, plastic bad 3 days for non washables
lyme disease
Borrelia spirochete, IXODES tick
NE US: MINNESOTA, WISCONSIN
ERYTHEMA MIGRANS
Tx: early doxycyline, amoxicillin, cefuroximine
bed bugs
CIMEX LECTULARIUS feed at NIGHT
all populations
spread: travel
linear array bites: breakfast, lunch and dinner
edematous papules scattered over the body, some excoriated (can have no rxn)
resolve 1-2 weeks
Tx: for symptoms antihistamines, topical steroids
launder bed linens, vacuum furniture, exterminator
risk factors for scabies
- women, children
- immunocompromised
- congregated facilities
crusted scabies
hyperkeratotic
thick, scaly, white-gray plaques with minimal itching
scalp, face, back, buttocks, feet
fissures provide entry for bacteria; sepsis, death
immune suppressed or neurological impaired
Tx: oral ivermectin, topical permethrin
ISOLATE
pediculus humanus var capitis
head lice
retroauricular and occipital scalp easiest to see nits
pediculus humanus var. corpis
body lice
back, neck, shoulder, waist
nits and lice on clothing
phthirus pubis
pubic or crab lice
lower abdomen, pubic area, thighs
