Acute Inflammatory and Eczematous Dermatoses PDF

Acute Inflammatory and Eczematous Dermatoses Urticaria (Hives) • Edematous plaques (wheals) o Erythematous-pink swelling o Dermal edema • Assc with: o Mast Cell Degeneration o Dermal microvascular hyperpermeability • Comes in 2 forms: Acute and Chronic • Transcytosis or vesiculovacuolar pathway caus...

Acute Inflammatory and Eczematous Dermatoses Urticaria (Hives) • Edematous plaques (wheals) o Erythematous-pink swelling o Dermal edema • Assc with: o Mast Cell Degeneration o Dermal microvascular hyperpermeability • Comes in 2 forms: Acute and Chronic • Transcytosis or vesiculovacuolar pathway cause increased vascular permeability • Prognosis/Management o Acute resolves in 1-4 days o Chronic has variable prognosis • Management: Antihistamine, glucocorticoids Erythema Multiforme/ Steven-Johnson Syndrome/ Toxic Epidermal Necrosis • Risk Factors: o Immune abnormalities o Type IV Hypersensitivity o 50% of idiopathic cases are from Herpes Simplex Virus • Classification: o Erythema Multiforme Minor § Target or raised Edematous papules o Erythema Multiforme Major § Target or raised Edematous papules § Involvement of one or more mucous membranes Classification of Erythema Multiforme Entity Common Etiologic agent Erythema Multiforme Minor Infectious w/o mucous membrane involvement Erythema Multiforme Major Infectious w mucous membrane involvement Steven Johnson Syndrome Drug Induced SJS/TEN Drug Induced Toxic Epidermal Necrolysis Drug Induced Epidermal Detachment % < 10% 10-30% > 30% • Pathophysiology o Cell Mediated Immunity causing epithelial apoptosis and inflammatory reaction § CD8+ and macrophages in epidermis § CD4+ in dermis o Transient TH1 cytokine response in circulating T cells (TNFµ, interferony, interleukin 2) • Affects skin and mucous o Skin: Target lesions § Central dark area § Pale, edematous zone § Peripheral erythematic rim o Oral: shallow ulcerations localized to: § Inferior tongue § Bilateral posterior buccal mucosa • Pathology: o Epidermal cell apoptosis o Basal cell vacuolar degeneration o Dermal lymphocytic infiltrate Acute Eczematous Dermatitis • Spongiotic dermatitis • Type IV Hypersensitivity • What is spongiosis? Widened intercellular spaces Allergic Contact Dermatitis • Assc w poison ivy, nickel, rubber gloves • Type IV hypersensitivity • Causes itching and burning • Pathophysiology: o Has extensive spongiosis o Possible intraepidermal vesicles o Numerous eosinophils o Pruritic papules and vesicles on an erythematous base Atopic Dermatitis • Skin barrier defects o Filaggrin (FLG) o SPINK5 mutation • Common sign: Brown macular ring around neck • Acute phase: Spongiosis • Chronic phase: Epidermal hyperplasia • Diagnosis: Biopsy and lab tests Questions • What kind of tinea is on the body? o Tinea corpora • Distinct feature of rubella? o Red, brown rash • Acute eczematous dermatitis, what pathologic feature is seen? o Spongiosis