Disease | Features |
Xeroderma Pigmentosum | increased incidence of cutaneous cancers as young child |
Ichthyosis | Genetic abnormalities in the maturation of keratinocytes |
Ichthyosis Vulgaris --> Ichthyosis Simplex or Hyperkeratosis Congenita | Incidence: 1/250, mc, autosomal dominant, formation of defective keratin --> diffic to desquamate --> hyperkeratosis, no granular layer in epid; onset in childhood, dry scaling in trunk and limb with sparing flexural areas, a/w atopy; some improv in adult |
Lamellar Ichthyosis (=ichthyosis Congenita, Collodion Baby, Harlequin Fetus) | Incid:1/300000, most auto recessive, mut in gene encoding keratinocyte transglutaminase(TGM1)on K14, prominent granular layer in epi, large coarse scales everywhere with thickened palms and soles, ectropion, incr.inc dehydr, elec imbal, no thrive, sepsis |
Epidermolysis Bullosa Simplex (aka EB, Epidermal type) | mc of EB, auto dominant, mut in keratin-5 gene (KRT5) on K12 or KRT14 on K17, blisters form by cytolysis within basal or spinous layers, abn density and organ of keratin filaments, usu on feet after traumatic injury, not a/w organ abn excp skin |
Weber-Cockayne Syndrome | EB Simplex confined to hands and feet |
Allergic Contact Dermatitis | Inflammation of skin with varying degree of erythema, edema, vesiculation d/t delayed type hypersensitivity rxn; Langerhans cells (w/in suprabasilar layer of epi)=antigen-presenting, interact with CD4 T lymph (=helper T cells) |
Contact Dermatitis | Inflammatory rxn that is NOT immune-mediated but rather caused by a direct toxic effect on the skin (gasoline) |
Urticaria | occurs following release of serotonin, histamine, bradykinin, kallikrein or ach --> Intradermal edema from capillary and venous dillation; d/t IgE contacting allergen -> hist released from mast cells; mediated by either complement fixation or meds |
Hereditary Angioedema | auto dominant, episodic appearance of brawny nonpitting edema, usu affect extremities (but also mucosal surf. of intestine (abdo pain)or resp tract (asphysia->requires intubation); heredit. deficiency of C1-esterase inhibitor; its serum C1INH is decreased |
Anaphylaxis | Immunopatho syst allergic rxn with urticaria and/or angioedema accompanied by hypotension and brochospasm;mediated by expos/ingest of allergen=generation of IgE=binds to mast cells and basoph; upon re-exposure, degranulat of mast&baso=relea of hist+inflam |
Anaphylaxis- Clinical Synopsis | More severe rx occur w/in min/hrs;parenteral faster/most severe, increa capill permeab leads to urticaria, angioedema and gener edema (mc),incr bronch smooth musc tone=wheezing, SOB, more secretion from mucous memb, decrea vasc smooth musc tone=hypotens |
Acute Eczematous Dermatitis | Most pts have positive family Hx for atopy (asthma, allerg rhinitis, atopic dermatitis),disordered immun resp in T-cell lymph(esp inbal of cyto), very pruritic erythematous&scaling plaques, bronchial asthma,recurrent urticaria,allerg rhinitis,high IgE lev |
Psoriasis | pathogenesis unknown, accelerated cell cycle for keratinocytes=overproduct, epid cells hyperadhesive (not desquamate)=formation plaque,immune dysregul in T cell,hyperplasia of epid a/w CD4Tcell inflam; some pt: psoriatc arthritis |
Seborrheic Dermatitis | Pathogenesis not known,Malassezia sp.organism=contributing cdition, Tcell depression/dysfxn, activation of alternative pathway, caused by aberrant cell-mediated immune response with IgM deposition in epidermis |
Discoid Lupus Erythematosus | Photodamage exposes or creates a heat shock protein w/in keratinocytes=acts as antigen target for Tcell-mediated epidermal cell cytotoxicity;deposition of immunoglobulin+complement at dermal-epid jxn |
Morphea | Lymphoplasmacytic infiltrate a/w dermal edema in early inflamm stage;late stage:excessive collagen deposition in dermis=atrophy of epid skin appendages,vasc obliteration,Tcells in dermis&subcutis, eosinophils present |
Pemphigus | bound+circulating complement-fixing IgG Ab directed against cell surface of keratinocytes;pemphigus autoantibodies bind to keratinocytes cell surface mol desmoglein 1&3->loss of cell-2-cell adhesion=acantholysis |
Pemphigus= Clinical features | Onset usu older adults,flaccid bulla mc lesion, oropharyngeal lesions, NIKOLSKY sign (sliding finger across skin->blister forms), healing w/out scarring, mortality 10% d/t complication fr mucosal ulceration&2ndary bacterial infection |
Paraneoplastic Pemphigus | PV dvping in pts w/ malignancies (non-Hodgkin lymphoma(mc),chronic lymph leukemia, Waldenstrom macroglobul, thymoma, bronchogen squam carcino);tumor antigens->cross-react IgG vs. keratino autoimmu resp to plakins;skin,GI, respira invol,morta90% d/t sepsis |
Benign Familial Pemphigus (Hailey-Hailey Disease) | Auto dominant w/ incompl penetrance, defect in keratino adhesion 2ndary to primary defect in Ca+ pump prot (ATP2C1) on K3, autoantibodies NOT present, onset usu 2nd decade, symp in intertriginous areas, chronic w/multipl relapses&remissions |
Bullous Pemphigoid | IgG autoantibodies directed vs. hemidesmosomal BP antigen BP230 (BPAg1)&BP180(tp17collagen)=complement activation+chemotaxis of neutrophils+eosinophils followed by inflammatory injury |
Dermatitis Herpetiformis | Deposition of IgA at epider-dermal jxn or in basement memb of mucosa=complement fixation+neutroph chemotaxis=vesicle form;sympto or asymp Celiac Disease/Celiac Sprue(gluten-sensitive enteropathy),increas incid of malignant lymphoma and primary GI lymphoma |
Erythrema Multiforme | hypersensitivity rxn that can be triggered by various stimuli, immune complex deposit variable;lymphocytic infiltrate in dermal-epi jxn&around dermal blood vessels a/w keratino necrosis and subepid bullae format,EM minor:sponta resolut;EM major:death 12% |
Stevens-Johnson Syndrome | 10% or less of total body surface area |
SJS/TEN Overlap Syndrome | 11-29% total body surface area |
Toxic Epidermal Necrolysis | 30% or more total body surface area involved |
Stevens-Johnson Syndrome/TEN complex | most a/w with meds use(usu sulfonamides or anto-seizure meds), dermis&epid accumul activated Tcells+macro=release cytokines(TN fact,gamma interferon,il2), full thickness epid necrosis begin @derm-epi jxn |
Erythema Nodosum | hypersensitivity rxn that occurs in relation to infection, systemic inflamm disease (Inflamm bowel, sarcoidosis) or med use; strep infections most common |
Acne Vulgaris | Presence of Proprionicbacterium acnes=metabolize fatty acids in sebum->abnormal sloughing of epithelial cells that line sebaceous follicles of skin->chronic plugging of pores |
Hidradenitis Supprativa | Recurrent bacterial infections of apocrine sweat glands, onset at puberty, increas incid in pt w/ autoimm disease, recurrent inflamm furuncles(nodules) that evolve into larger draining carbuncles(subcut abscesses);fistulous tracts,scarificat,squam carcino |
Drug-Induced Bullous Disease | greatest incidence w/semisynthetic penicillins&sulfamethoxazoles/trimethoprim;bullous drug rxn=result of immuno mediated inflamm response, primarily activation of drug-spec CD8Tcell;almost all resolve spontaneously up discontinu of drug,reccurrence common |
Henoch-Shonlein Purpura | Type3 immunopatho disease(immune complex deposition), vasculitis d/t deposition of immune complex in small blood vessels+capill;IgA+activated C3;more than 95% resolve spontaneously, minority:dvp chronic renal failure d/t glomerulonephritis |
Laceration | Tissue bridging present |
Incised Wound | Tissue bridging NOT present |
Animal Bite Wound | Common pathogens: Pasteurella, S. Aureus, Anaerobes |
Human Bite Wound | If distance btw canines more than 2cm, then adult inflicted wound, if less than 2cm, child inflicted wound; look into child abuse |