Hypersensitivity Syndromes

Question 1

Erythema Multiforme:

Answer 1

• Acute, Self-limited inflammatory
• Targetoid Acral lesions
• PRECIPITATED BY VIRAL OR INFECTIOUS PATHOGENS
• Does not progress to TEN
• EM Major: Mucosal and systemic involvement
• EM Minor: no systemic symptoms
• MOST COMMON AFTER HSV-1 OR HSV-2
• Mainly viral precipitation
• NSAIDs

Question 2

Steven Johnson Syndrome/Toxic Epidermal Necrolysis:

Answer 2

• Same disease but on spectrum
• Severe drug reaction
• Fever, mucosal erosion, SKIN DETACHMENT OCCURRING 1-3 WEEKS AFTER MEDICATION
• Less than 10% BSA affected
• Greater than 10% BSA is TEN
• Can evolve into TEN
• Inability to detoxify drug metabolites
• Cell mediated immune response -> activates cytotoxic T cells -> induce keratinocyte apoptosis via cell surface signalling
• Rapid Diagnosis via skin biopsy
• Positive Nikolsky Sign

Question 3

Neutrophilic Dermatoses:

Answer 3

• Sweet’s Syndrome
• Erythema Elevatum Diutinum
• Pyoderma Gangrenosum

Question 4

Sweet’s Syndrome:

Answer 4

• Acute Febrile Neutrophilic Dermatosis
• Painful plaques with fever
• Women head neck trunk
• Leukemia, Pregnancy, Autoimmune
• Fever Precedes Skin Lesions
• Respiratory most common system involved

Question 5

Erythema Elevatum Diutinum:

Answer 5

• Form of leukocytoclastic vasculitis
• Immune complex deposit in small vessels cause inflammation
• Infectious agents, hematologic manifestations, IBD, RA
• Violaceous red or brown lesion on EXTENSOR surfaces

Question 6

Pyoderma Gangrenosum:

Answer 6

• Inflammatory noninfectious ulcerative neutrophilic skin disease
• Pathergy: Surgery exacerbates
• Diagnosed by exclusion

Question 7

Erythema Nodosum:

Answer 7

• Most common inflammatory panniculitis (inflammation of subcutaneous adipose)
• Symmetrical PRETIBIAL REGION
• Children: Streptococcal
• Adults: Sarcoidosis, IBD, Oral contraceptives
• Go away
• Do not ulcerate
• SKIN BIOPSY REVEALS SEPTAL PANNICULITIS