Exam 3 part 2 acute skin infections Flashcards
What are the hallmarks of urticaria?
transient wheals, pruritic, type 1 hypersensitivity (IgE). HIVES
What are the hallmarks of angioedema?
swelling of lips, burning pain, emergency
What are the hallmarks of Steven Johnson syndrome?
2+ Mucous membranes,
What causes Steven Johnson syndrome?
Hypersensitivity to sulfa drugs (often a treatment for UTIs)
What are the hallmarks of erythema multiforme
Target lesions on palm, 1 mucous membrane
What are the hallmarks of Toxic Epidermal Necrolysis
2+ mucous membranes, 30+% skin sloughing
What are the hallmarks of fixed drug reaction
1 spot of hyper pigmentation, start demarcated lines
What are the hallmarks of erythema nodosum
Anterior leg nodules
What are the hallmarks of Erythema induratum
posterior leg nodules
Whats the difference between erythema nodosum and induratum?
EN is the anterior leg nodules, EI is the posterior leg nodules
What layer of skin does urticaria affect?
Dermis
What layer of skin does Erythema multiforme affect?
Epidermis and Dermis
What layer of the skin does Steven Johnson Syndrome and Toxic epidermal necrolysis affect?
Epidermis and Dermis
What layer of the skin does fixed drug eruption affect?
Epidermis
What layer of the skin does panniculitis (Erythema nudism and erythema induratum) affect?
Subcutaneous
What layer of the skin does angioedema affect?
Deep dermis and subcutaneous
What needs to be done when seeing a patient with urticaria or angioedema?
Thorough history (travel, recent infection, occupational exposure, meds, foods) Careful family history for pre-existing allergies, Look at total body (joints, skin surfaces, mucosal membranes)
How often are angioedema and urticaria acute reactions?
Over 2/3rds of all these reactions are acute
Immune causes of urticaria and angioedema?
Type 1 IgE mediated (allergies), auto-immune (SLE, hashimoto’s immune thyroiditis, infectious agent (viral, bacterial, etc)
Non-immune causes of urticaria and angioedema?
Physical urticarias (ice, sun, friction, pressure), direct mast-cell degranulation (narcotics, aspirin, NSAIDs), foods containing high levels of histamines (strawberries, tomatoes, shrimp)
Different lab exams to evaluate urticaria and angioedema
CBC, ESR, TSH, basica chem panel, anti-thyroid antibodiy and FANA in female patients, punch biopsy to exclude vasculitis if lesion persists for 48 hrs
What is the therapy for angioedema and urticaria?
Avoid allergen, avoid extremes in heat and cold, exercise, alcohol. Acute: antihistamines non-sedating H1 blockers
name First choice antihistamines for treatment of urticaria and angioedema?
Second generation, non-sedating H1 blockers: Cetirizene (10-20mg/day), Fexofenadine (180mg/day), Desloratadine (5mg/day) , Loratidine (10mg/day)
What is the last resort for antihistamines
Oral corticosteroids (prednisone, tapered over 10-14 days), EpiPen for type 1 IgE mediated
What would you diagnose someone who comes into the clinic with bulls-eye lesions on their extremities (palms and soles) with?
Erythema multiforme
What can cause erythema multiforme?
50% is idiopathic, drugs: sulfonamides, phytoin, barbituruates, phenylbutazone, penicillin, allopurinol. Infection: HSV, Mycoplasma
What are the two forms of Erythema Multiforme?
EM minor (1 mucosal site, usually post-HSV infection), EM Major (SJS, usually due to drugs
What usually causes erythema multiforme minor?
Post herpes simplex infection, EM rash at day 10
What usually causes EM major?
Due to drugs (sulfa, PCN, dilantin, tegretol), and after mycoplasma pneumonia infection
What is the therapy for erythema multiforme?
Prevention of HSV outbreaks, glucocorticoids for severe systemic illness
T/F: SJS and TEN can be life threatening?
Yes
How do you differentiate between EM and SJS and TEN?
EM (1 membrane)>SJS ( TEN (30% of epidermal detachment, 2 membranes)
What are risk factors for SJS and TEN?
systemic lupus, HLA-B12, HIV disease
What is the leading causative factor of SJS and TEN?
SJS: 50% associated with drugs, TEN: 80% associated with drugs
How long does it take for SJS and TEN to develop after first drug exposure?
1-3 weeks, detachment is equivalent to a 2nd degree burn
Treatment of SJS and TEN?
early diagnosis and withdrawal from drug, ICU, management of IV fluids, early glucocorticoids, high dose of Ig for TEN, debride only frankly necrotic skin, treat complications
What are complications of SJS and TEN?
sepsis, GI hemorrhage and fluid/electrolyte imbalance
Where do fixed drug eruptions happen?
face and genitals most common
How do you treat fixed drug eruptions?
remove offending drug
What are the two forms of panniculitis?
Erythema nodosum, erythema induratum
How do you accurately diagnose panniculitis?
skin biopsy
What triggers erythema nodosum?
Infection (strep, TB, infection) Meds (OCP, sulfa, NSAIDs), autoimmune (BD, sarcoid)
What is erythema induratum usually associated with?
TB
How do you treat panniculitis?
rest, ice, pain control
