Eczemas and Allergic Skin Diseases 2 (Adverse Drug Reactions) Flashcards
Erythematous eruptions (abrupt onset)
most mild, can be severe and life threatening in some cases
Drug eruptions can ____ any inflammatory skin condition
mimic
“Developing a rash while taking a medication is a drug eruption until proven otherwise.”
Most erythematous eruptions in children are?
viral exanthems
Most erythematous eruptions in adults are?
drug eruptions
Simple drug eruptions
rash (skin) only; antibiotics mostly cause these; no lab findings
Complex drug eruptions
constitutional symptoms; sulfonamides/allopurinol/anticonvulsants; show abnormal labs (liver and kidney function)
Exanthematous drug eruptions
these are 90% of cases; mixed I and IV; pt’s history is important
take up to 1 wk on first exposure, 1-2 days if previously exposed
immediately withdraw drug, topical steroids
Urticaria (hives)
pruritic skin eruption, with blanchable wheals in varying sizes
ind. lesions resolve in 48 hours, while new ones are developing
Angioedema
swelling of subcut. tissue (usually near eyes and mouth) and mucosa of GI and respt. tract
resolves in 2-4 days
Anaphylaxis
severe allergic reaction
laryngospasm->airway obstruction/vascular collapse->hypotension
occurs within 1 hr of exposure
Pathophysiology of urticaria and angioedema may be an _______ or _______ mechanism
allergic; non allergic
not limited to a drug reaction
Various causes of Urticaria and/or Angioedema
drugs, insects, foods, parasitic infections, latex, aeroallergens, pressure
Physical Uticaria
resolves in 2 hours (stress, anxiety, etc)
Acute Uticaria
ind. lesions resolve in 24-48 hrs, reaction resolves <6 wks with no confounding symp.
what you think of when you think of an allergic reaction
RAST test appropriate
Chronic Uticaria
ind. lesions resolve in 24-48 hrs, reaction resolves >6 wks with no confounding symp.
possibly autoimmune disorder
*refer case
Uticaria with vasculitis
ind. lesions last longer than 48 hrs and have confounding symp. such as hives, fever, and vasculitis
* refer case
Angioedema without uticaria what is likely cause?
ACE inhibitors
No history of ACE inhibitors what is angioedema without uticaria likely caused by?
Hereditary angioedema (HAE)
Blood test to identify hereditary angioedema
C’1 Esterase Inhibitory (C’1 INH)
Antihistamines: H1 blockers
block histamine receptors in skin and vasculature
Antihistamines: H2 blockers
block histamine receptors in parietal cells
Erythema Multiforme (EM)
cutaneous reaction to antigenic stimuli; sometimes as drug reaction but usually reaction to herpes simplex virus
Erythema Multiforme: Minor
target lesions and vesicles on extremities. little mucous membrane involvement, no systemic symp
Erythema Multiforme: Major
target lesions with vesicles and bullae (blisters) on extremities also involving mucous membranes, systematic symp.
Emergency-may have detachment of large sheets of skin
EM Major may have a positive ___________.
Nikolsky sign or phenomenon (epidermis dislodged from dermis)
EM that results as a drug reaction is usually EM ____?
Major
EM major treated with?
oral corticosteroids
EM minor treated with?
antivirals
Steven-Johnsons Syndrome
acute, life threatening reaction to drugs that result in extensive necrosis and detachment of epidermis
<10% epidermal detachment
10-30% overlapping SJS and TEN
Toxic Epidermal Necrolysis (TEN)
same as Steven Johnsons Syndrome, just more severe
>30% epidermal detachment
Average mortality for SJS is
5-10%
Average mortality for TEN is
30%
SJS and TEN have what attributes?
target-like lesions or diffuse erythema that progress to necrosis and epidermal detachment; may occur over a few hours to days, severely painful, fever, tachycardia
SJS and TEN treatment?
discontinue drug!! prevent recurrence by never administering drug again
hospitalize and treat like burn pt. with fluids and electrolytes
avoid debridement; treat complicating infections
