Contact derm Flashcards
chemical prod paresthesia of fingertips w cyanosis and gangrene. nails yellow.
oxalic acid.
oxalic acid is best neutralized a what?
lime water
milk of magnesia.
is a protoplasmic poison prod white eschar om skin.
may prod glomeruloneph, arrhythmia
Phenol (carbolic acid). neutralized by 65% ethyl or isopropyl alcohol.
phosphorus burns tx
Rinse w water.
ff by app of copper sulfate to prod precipitate.
wht chemicals expand the airbag?
sodium azide and cupric oxide propellant cartridge release nitrogen gas w expands bag exceeding 160kph (96 mph)
Dusts of what prod folliculitis.
Lime, Zinc, Arsenic.
Capsaicin dermatitis tx
Insoluble in water.
Acetic acid 5% ( white vinegar) or antacids (maalox) relieve the burning.
What us chloroacetophenone
Lacrimator for tear gas dermatitis.
delayed appearance 24 -72 hrs after exposure.
irritation, sensitizaruon w erythema and severe vesiculation.
Tx for tear gas dermatitis
Lavage agfected skin w sodium bicarbonate sol and instillation of boric acid solution in eyes.
what is yperite (dichlorodiethyl sulfide)
used jn chemical warfar. sulfur mustard gas. Erythema vesicles bulla used in chemical warfare.
most freq affected sites are covered by clothing, humidified by sweat, groin axilla genitalia
What is chloroacetophenone
Mace a mixture of tear gas
causes allergic sensitizaruon.
tx : chnge clothes, washing w oil/ milk. ff by washing w water
crude petroleum prod what lesions
Itching folliculitis acneiform eruptions.
Solvents cause approx how many percent if occupational dermatitis?
10%
allergic contaxy derm hs what hypersensitivty type?
type 4 hypersistivity
Cell mediated
Tx acute general allergic contact derm
Syst steroid beginnig w 40-60mg/day of prednisone in a single oral dose. tapering slowly to topical steroid.
Eruption limited- Local app of top steroid cream, lotion, aerosol spray.
strong patch test reactions induce a hyperirritability also called as what sundrome
Excited skin syndrome
a std patch test is applied for how many hrs?
48 hrs. then exposed to 5 to 15 j/m2 of UVA and read for another 48 hrs.
most frequent site for nail polish dermtitis?
Eyelids
Toxicodendron ( Poison ivy) dermatitis appeara after how many hrs after exposure?
what is the 1st symptom?
48 hours.
marked pruritus is the 1st symptom.
black dot sign is seen in where?
Poison ivy reaction
tx poison ivy
eruption severe or extensive- Sys steroid begin 40-60 mg prednisone single oral dose daily tapered off over a 3 week period.
most common cause or allergic cont derm in florists
Peruvian lily
seaweed dermatitis is caused by a marine blue green alga caled
Lyngbya majuscula Gomont.
reported to cause hemorrhaguc bullae on the feet of farmers.
Randox (2- chloro- N, N- diallyl- acetamide)
trimming during landscaping induce irritant derm caused by
Calcium oxalate crystals.
Best screening agents for drmatitis from clothing.
Ethylene urea melamine formaldehyde resin.
Dimethylol dihydroxyethylene urea formaldehyde resin
shoe dermatitis is most freq caused by the ff rubber accelerators.
Mercaptobenzothiazole, carbamates, tetramethylthiuram disulfide
preservative used in antihumidity sachets.
Dimethyl fumarate.
most common causw of allergic contact derm in children and adults
nickel
in a patch test rxn. Nickel xan be detected by applying wht to the test object?
ahat is the positive xolor rxn
Dimethyl- glyoxime solution
cotton swab used to apply the sol will turn orange- pink.
dental gold lesions
oral lichenoid eruptions
what chemical is the most often the cause for shoe allergy and glove allergy.
Mercaptobenzothiazole- Shoe allergy.
Thiuram- Glove allergy
among transdermal meds which one induces the highest rate of allergic rxn?
Clonidine
contact urticaria ans anaphylaxis are reported most often w what drug? Than w other antibiotics.
bacitracin
4 structural classes of corticosteroid.
Class A- Hydrocortisone; Tixocortol pivalate grp B - Triamcinolone acetonide, budesonide grp C- Betamethasone grp D- hydrocortisone 17- butyrate group.
freq cross reactions bet B and D.
Tixocortol pivalate and budesonide - best screening agents.
are these immunologic or non immunologic reactions? latex, potatoes, phenylmercuric propionate
IgE mediated type.
Immunologic type
What are non immunologic type?
Does not need prior sensitization. nettle rash ( plants), DMSO; sorbic acid, benzoic acid, cinnamic aldehyde, cobalt chloride, trafuril.
vast majority of drug reactions.
Simple exanthem (75-95%) Urticaria (5-6%)
females 1.3-1.5 times more. except under age 3 yo the boys are most likely affected w drug reactions.
RAST has how many percent false negative results rate in penicillin type 1 allergy.
20%
useful in eval type 1 immediate hyper rxnz
skin testing
Exanthem in adverse drug rxn spares the face, if its not spared what is the dx considered?
DRESS
most common cause of drug rxn?
Penicillin
TMP SMX
Ampi - amox given during ebv infectuon cases how many percent exanthem in adults and children
29-69%- adults
100%- children
TMP given to aids pxs causes exanthem in how many percent
40%
antimalarials % in exanthem
25 percent
overall incidencd of DRESS.
1/1000 and 1/10000
characteristix feat of DRESS
Rash
long lastings symptom
fever greater 38
Multiorgan inv
CBC : Eosinophilia - > 1500 absolute eosinophilia
lymphocyte activation
Frequent reactivation of HHV6, HHV7; EBV, CMV, (60-80% of cases demonstrate HHV family reactivation)
skin eruption in DRESS
Morbilliform
others:
facial erythema
edema periorbital sparing
impetigo like crusting on chun
allopurinol minocycline w has renal or pulmo involvement.
Allo- Renal
Mino- Pulmo.
first line tx DRESS
Stop causative agent High dose sys steroid (1-2 mg/kg/day) Pulse IV steroid IVIG cyclosporine
most common anticonvulsant causing dress
Carbamazepine
after how many weekds after starting medicarion does sulfonamide hypersensitivity syndrome occur
3 weeks
minocycline hyperses syndrome, pxs has deficiency or what enzyme
Glutathione S transferases
minocycline hypersens. percent of liver and renal involvement.
Liver 75%
Renal 17%
dapsone hypersesy. most characteristic lesion and tx
Morbilliform eruption that heals w desquamation.
icterus and lymphadenopathy. -80% of pxs.
Tx- corticosteroids. mainstay
SCORTEN is scoring for what?
TEN/ SJS most common model to predict mortality
SCORTEN Scoring w percent mortality.
0-1 - 3.2% mortality
>5- 90% mortality
histo SJS ten
Lymphocytic infiltrate at DEJ
necrosis of keratinoxytes
cellular necrosis
TEN has elevated what ligand
ELEV FAS ligand
FAS TEN
in europe what is yhe most common cause of Sjs ten (drug)
in children?
allopurinol.
children- sulfonamides, antibioticsF antieleptics. acetaminophen.
what scoring can be used to point out causality in sjs ten
ALDEN score
what HLA haplotype is present in vast majority of carbamazepine induced SJS/TEN patients?
HLA B 1502
Mechanism for IVIG In TEN.
Blocking binding of FasL To Fas, stopping keratinocyte apoptosis.
Ave time of epidermal regrowth who survive sjs ten-
3 weeks
most common sequelae of sjs ten
Ocular scarring
vision loss
