Dermatopathology II

Disease	Pathogenesis	Pathology	Clinical Features/ Treatment
Erythema nodosum	trigger: drugs, microorganisms, systemic diseases drugs: sulfonamides	fibrous septa of subcutaneous tissue - neutrophil inflammation, extravasation of erythrocytes chronic - septa widened, giant cell macrophages, altered collagen	dome-shaped, tender, nodules on extensor surface of legs 3rd decade, 3xF:M
Erythema induratum	Mycobacterium tuberculosis	initially lobular panniculitis, vasculitis - ischemic necrosis of fat lobules dense, chronic inflammatory infiltrate in fat lobules extensive ischemic necrosis - ulceration of overlying epidermis	chronic, recurrent, subcutaneous plaques or nodules on legs, women T - systemic steroids
Scleroderma		pathcy lymphocytic infiltrate, loss of peri-eccrine fat, plugging of sweat glands, obliteration of hair follicles, subcutaneous fat turns into collagen	fibrosis and tightening of skin mask face 4xF:M, 30-50y non-pitting edema of hands or fingers
Granulomatous dermatitis	localized collection of epitheliod macrophages around insoluble antigen
Allergic Contact dermatitis	sensitization - haptens: oleoresins, Langerhans Cells - CD4+ T cells Elicitation - activated T cells, IFN-gamma - Fas ligand on keritanocytes - apoptosis	spongiotic dermatitis - edema in epidermis spongiotic vasculitis - vacuoles filled with lymphocytes and macrophages	immune rxn to poison ivy, poison oak, poison sumac

Source: Rubin's Pathology 4th Edition