Cutaneous Reaction Patterns Flashcards
What is the type of lesion seen in urticaria?
Describe the etiology.
What other signs is it associated with?
Wheals.
Mast cell degranulation (Type I HSR).
Angioedema, anaphylaxis.
What can provoke urticaria?
How can it be treated?
Idiopathic, but especially URIs and allergies (eg food)
Antihistamines.
What is the most common skin response to a drug?
How rapid is this response?
Exanthemous drug eruptions, AKA morbilliform drug rashes.
Takes 2-14 days for eruption, resolves after 1-2weeks.
What are the symptoms of a morbilliform drug rash?
How is it treated?
Pruritis, increased blood count & liver panel.
Antihistamines. Can probably stay on the offending drug.
What is DRESS??
What can trigger it?
Drug Reaction with Eosinophilia & Systemic Symptoms
Most common: Anti-epileptics, Sulfonamides, Minocycline, Allopurinol, Anti-retrovirals.
What are the symptoms of DRESS?
What organs are involved?
How is it treated?
Facial edema, lymphadenopathy, fever. Morbilliform rash of course.
Liver, bone marrow, kidneys (mainly)
Stop the offending drug, give corticosteroids.
Erythema Multiforme
Etiology?
Signs?
Treatment & outcome?
Erythema Multiforme
Viral infections or drug hypersensitivity.
Targetoid lesions on acral sites. Sometimes mucosal.
Corticosteroids, pain management. Good outcome.
How are Erythema Nodosum, Stevens-Johnson Syndrome, and Toxic Epidermal Necrolysis related?
SJS and TEN overlap significantly. EM was formerly thought to be related.
Stevens-Johnson Syndrome
Etiology?
Signs?
Treatment?
Stevens-Johnson Syndrome
Hypersensitivity reaction. Unknown pathophysiology.
Painful red patches that evolve into blisters, necrosis. Affects skin & mucosae.
STOP offending substance. Maintain fluids & pain.
Stevens-Johnson Syndrome
Who is at risk?
What is the “prodrome”?
How does TEN relate?
Stevens-Johnson Syndrome
Women, HIV/SLE patients, those with cancer & certain HLAs.
Prodrome = flu-like illness that precedes cutaneous symptoms.
TEN is SJS that exceeds 30% of body involvement.
What are the most common causes of leukoclastic vasculitis?
What are its clinical signs?
Does it affect large or small vessels?
Many idiopathic. Otherwise, infections & drug reactions, exacerbated by autoimmune diseases & malignancy.
Palpable purpura, systemic involvement (fever, myalgia, etc)
Affects small vessels.
Is takayasu arteritis involving large or small vessels?
Henoch-schonlein purpura?
Large
Small
What is the treatment & prognosis for LCV?
Treat underlying trigger. Steroids & immunosuppressives.
If skin-limited, good. Otherwise, not so good.
Henoch-Schonlein Purpura is often associated with a leukocytoclastic vasculitis. What is the most common cause of this?
What does direct immunofluorescence reveal?
Strep URI.
IgA immune complexes.
What are the hallmark findings of HSP?
What is the treatment & prognosis?
Palpable purpura on the buttocks & legs. Sometimes face & arms.
Treatment: Antihistamines, corticosteroids, NSAIDs. Skin usually resolves, but systemic involvement can be longer-lived (eg Nephritis)
