Dermatology Flashcards
5 epithelial cell junctions
Tight J.: prevents paracell mvt of solutes
Adherens J.: cadherins (actin + E-cadherin)
Desmosome: keratin interactions (AutoAb: pemph vulg)
Gap J.: connexons permit electr/chemic communication
Hemidesmosome: keratin+basement mmbrn (AutoAb: bullous pemph)
Atopic dermatitis/eczema (RF, PE)
Chronic inflam/pruritus then lichenification
Fam Hx: asthma/eczema/allergic rhinitis
↑ risk of 2* skin infection (Staph aureus/HSV/molluscum)
Triggers: climate, food, skin irritants, allergens, emotions
Infants (face/scalp/extensor surf/NO diaper), children (flexor surf/neck), adults (flexor surf/eyelid/hand)
Eczema (dg, ttt)
dg: erythema toxicum neonatorom (d 1-3), benign, resolves in 1-2wks w/o ttt
Dg: clinical, KOH prep to r/o tinea
ttt: topical CS (#1), topical immunomodulator (>2yo, sparing CS)
CS intermittently to avoid skin atrophy
Skin care (↓ pruritus) + antihistamines
Contact dermatitis (PE, dg, ttt)
dg: latex allergy is a type I HS (not this)
Type IV HS / allergen (makeup/nickel/poison ivy/top AB)
Pruritus/rash (mimics the shape)
Spread to body: transfer of allergen (hands) or T lymphoc
Dg: clinical, patch test (after ttt of acute phase)
ttt: topical CS + allergen avoidance
Type I hypersensitivity
Anaphylactic and atopic
Ag cross-links IgE on presensit mast cells
Vasoactive amines (histamine) release
Fast
Type II hypersensitivity
Cytotoxic
IgM/IgG bind to Ag on bad cell: lysis by complement or phagocytosis
Type III hypersensitivity
Immune complex (Ag/Ab) activate complement, attract PMNs, release lysosomal enz
Serum sickness: Ab+foreign Ag deposit, fix to complement and damage tissue
Arthus reaction: Ab react to Ag, vascular necrosis/thrombosis
Type IV hypersensitivity
Delayed (cell-mediated)
Sensitized T lymphoc react to Ag, macroph activation
No Ab
Seborrheic dermatitis (PE, dg, ttt)
Chronic inflam / hypersensitivity to Malassezia furfur (in sebum/hair follicles)
Infants (diaper/scalp), children/adult (ears/eyebrows/nasolabial fold/midchest/scalp)
Severe in HIV/AIDS and Parkinson
Dg: clinical
ttt: selenium sulfide or zinc pyrithione shampoos (adult), topical antifungals +/- topical CS
Infant scalp resolves w/ bathing+emollients
Stasis dermatitis
Lower extremity, venous hyperTN by venous valve incompetence/flow obstruction
If unttt, inflam/exudation/hyperpigm
Stasis ulvers
ttt: early w/ leg elevation, compression stockings, emollients, topical steroids
Grouped vesicles + fever after eczema ttt w/ CS
Eczema herpeticum
Medical emergency
HSV infection spreads systemically (+ brain)
IV acyclovir immediately
Psoriasis (PE)
T-cell mediated infl
Dermal infl + epidermal hyperplasia (+ parakeratosis)
Extensor surf/scalp/lumbosacral/nails/pso arthritis (hands/feet)
Drugs that worsen (B-/lithium/ACEIs)
Psoriasis (dg, ttt)
Dg: clinical, Auspitz sign, biopsy (if uncertain)
ttt: topical steroids, calcipotriene (vitD), tazarotene (vitA)
Severe or w/ pso arthritis: methotrexate or antiTNF (etanercept/infliximab/adalimumab)
UV if extensive involv (CI in immunosuppressed)
Urticaria/hives (PE)
Histamine/prostaglandins from mast cells in type I HS
Superficial erythema/edema, acute/chronic (>6wks)
Dermal edema, may become confluent
Severe w/ extracut: tongue/angioedema/asthma/GI/joint/fever
Urticaria/hives (dg, ttt)
Trigger in acute: food/drug/virus/insect bite/sun/cold/heat
Idiopathic in chronic
Dg: clinical
ttt: systemic antihistamines
Anaphylaxis: epinephrine IM, antihistamines, IV fluids, airway!
Drug eruption (PE)
Mild morbilliform rash to life-threatening TEN
High suspicion in hospit ptts after 7-14d from drug expo
Any type of HS
Widespread eruption, symmetric, pruritic
Eosinophilia
Drug eruption (dg, ttt)
Disappear 1-2 wks of removal of drug
Dg: clinical, biopsy if unclear
ttt: stop drug, antihistamines + topical steroids
Erythema multiforme (PE, dg, ttt)
Targetoid lesions, recurrent, +/- fever/myalgias/arthralgias/headache Many triggers (HSV/mycoplasma)(Not drugs so #SJS)
Esp palms/soles
Major: skin + mucous membranes (#SJS)
Dg: clinical (Nikolsky sign neg)
ttt: just symptomatic
Stevens-Johnson sd / Toxic epidermal necrolysis (RF, PE)
Life-threatening exfoliative mucocutaneous ds
Often drug-induced immuno reaction
Epidermal separation: SJS <10%BSA, TEN >30%BSA
Severe mucosal erosions, widespread confluent erythem lesions; Nikolsky positive
Ass w/ sulfonamides, penicill, seizure meds, quinol, cephalosp, steroids, NSAIDs
Stevens-Johnson sd / Toxic epidermal necrolysis (dg, ttt)
SJS: degeneration of basal layer of epidermis
TEN: full-thickness eosinophilic epidermal necrosis
#dg: SSSS, GVHD, radiation therapy, burns
ttt: early dg + d/c drug
Thermoregul+e- disturb, 2* inf → cover skin + fluids/e-
Steroids? Cyclosporine? IVIG?
Erythema nodosum (etiologies, PE)
Panniculitis (infl of subcut adipose tissue)
Causes: inf, drug, chronic infl ds
Painful erythem nodules, ant shins, turn brown
+/- fever, joint pain
! false+ VDRL
Erythema nodosum (dg, ttt)
Dg: clinical + workup for underlying cause
ttt: underlying cause, NSAIDs/cool compresses, potassium iodide (if persistent)
Bullous pemphigoid
AutoAb ag. hemidesmosomal prot
Firm/stable blisters, Nikolsky neg, rare mucosal involv
Esp. >60yo, idiopath
Rare mortality
Dg: clinical +/- biopsy (w/ direct immunofluo)
ttt: steroids
Pemphigus vulgaris (etiologies, PE)
AutoAb ag. desmoglein (intraepidermal) Erosions, No keratinocyte adhesion Nikolsky positive, common mucosal involv Esp. 40-60yo Ass w/ ACEIs/penicillamine/phenobarbital/penicillin
Pemphigus vulgaris (dg, ttt)
Possible mortality
Dg: clinical +/- biopsy (w/ direct immunofluo)
ttt: high-dose steroids + immunomodulator (azathioprine, mycoph mofet, IVIG, rituximab)
Herpes simplex virus (PE)
Painful/recurrent/mucocutaneous/ +/- systemic sympt
HSV-1 oral-labial; HSV-2 genital
Direct contact→ 1* episode longer/severe→virus dormant in nerve gg
Recurrences: cold sore (trigg by sun/fever); unilat genit herp
#dg: dermatitis herpetiformis (prurit papul/vesic/bull) elbow/knee/butt/neck/scalp ass w/ celiac ds ttt: dapsone + gluten-free
Herpes simplex virus (dg, ttt)
Dg: clinical, viral culture of lesion (accurate), direct fluores Ag (rapid)
Multinucleated giant cells on Tzank smear
AIDS-defin illness = symptom ulcers resist to antiviral >1mo
ttt 1* episode: support ttt or acyclovir/famcyclovir (Icompet); antiviral in 72h of start (Icomprom or severe)
ttt recurr: support (minor lesion) or acy/famcy/valacyclo to ↓ 2d
ttt severe+fqt (>6/y): daily prophyl acy/famcy/valacyclo
Varicella-Zoster virus (PE)
Respiratory dropl/direct contact; incubation 10-20d
Contagion 24h before eruption till crusted lesions
Varicella: malaise/fever/headache/myalgia 24h before rash; pruritic lesions over 2-3d; crust; all stages at any time; adults more severe (+pneumonia/encephalitis)
Trunk/face/scalp/mucous membranes
Zoster: recurr of VZV in one nerve/dermatomal; intense pain then eruption; dissem in Icomprom; postherp neuralgia in older ptts.
Varicella-Zoster virus (dg, ttt)
Dg: clinical
ttt: varicella self-lim (children) + vaccine available
Adults: systemic acyclovir + pain control (gabap/TCA)
Postexposure prophyl: rare (bcz ds/vacc in almost all).
Icompetent adult: vaccine in 5d of expo
Icomprom/pregnant/newborn: Ig in 10d of expo
Molluscum contagiosum
Poxvirus; esp children/AIDS
Direct contact/sharing cloth
Small flesh-colored papules, central umbilic, asymptom
If giant: HIV or Icomprom
Child (trunk/face); adult (genital/perineal); No palm/sole
Dg: clinical; large inclusions on microsc
ttt: curetting/freezing/trichloroacetic acid
In kids, spontan resolution
Verrucae/Warts
HPV; benign or malignant (16/18)
Direct contact; found on skin(hands)/mucous/epithelia
Genital warts (condyloma acuminatum): HPV 6/11
Laryngeal warts in infants of affected women
Dg: clinical; acetic acid for mucosal lesions (turn white); PCR of HPV (accurate)
ttt: locally for genital W (cryoth/podophyllin/trichloroacetic acid/imiquimod/5-FU); monitor cervical lesions (! malign)
Impetigo (PE)
Inf of epidermis; esp child; direct contact
By group A strep (complic by PSGN) or Staph
Common type: pustul/crusts; face (mouth/nose/ears)
Bullous type: bulla/crusts; acral; by Staph aureus, can evolve into SSSS
Impetigo (dg, ttt)
Dg: clinical
ttt:
Mild/local: topical AB (mupirocin)
Severe (non-MRSA): oral cephalexin, dicloxacillin, erythromycin
Severe + MRSA: oral TMP-SMX, clindamycin, doxycycline
Skin infections according to skin layers
Epidermis: impetigo Hair follicle: folliculitis Dermis: erysipelas, cellulitis Subcut fat: cellulitis, necrotizing fasciitis Fascia: necrotizing fasciitis Muscle: necrotizing fasciitis
Cellulitis (PE, dg)
Inf of dermis+subcut tissue; by damaged skin/systemic
By staph or group A strep; communit-acqu MRSA
RF: DM, IVDU, venous stasis, Icomprom
Red, hot, swollen, tender skin +/- fever/chills
Dg: clinical, cultures (dg+suscept)
R/O abscess, osteomyelitis, necrotizing fasciitis
Cellulitis (ttt)
ttt: 5-10d oral AB
IV if systemic toxic/comorbid/DM/extreme age/hand or orbital involv
Mild/local: topical AB (mupirocin)
Severe (non-MRSA): oral cephalexin, dicloxacillin, erythromycin
Severe + MRSA: oral TMP-SMX, clindamycin, doxycycline
Erysipelas
Ludwig angina
Erysipelas: type of cellulitis; strep; dermis and lymphatics; raised indurated well-demarcated erythematous skin
Ludwig angina: bilateral cellulitis of submental/submaxillary/sublingual; from infected tooth; dysphagia, drooling, fever, red warm mouth; death from asphyxiation
Scarlet fever
Salmonella typhi
Scarlet fever: sandpaper rash, strawberry tongue; Strep pyogenes; ttt Penicillin
Salmonella typhi: small pink papules on trunk, groups 10-20, fever, GI sympt; ttt Fluoroquin and cephalo-3G
Cholecystectomy for chronic carrier
Necrotizing fasciitis (PE)
Deep inf along fascia; Hx of trauma, recent surgery
Mixed inf: anaerob + aerob bacteria (S aureus, E coli, Clostr perfring, Strep pyogenes)
Severe acute pain/swelling then anesthesia; erythema; progression; purple near insult; necrosis
Necrosis: crepitus (gas), putrid disch, bullae, severe pain
Necrotizing fasciitis (dg, ttt)
Dg: clinical exam + imaging
ttt: surgical emergency (exploration + aggressive debridement, cultures)
Broad-spectrum: peni G (if strep), clindamycin (↓ toxin); metronidazole or cephalo-3G (for anaerob)
Fournier gangrene: necrot fasc localized to genital/perineal area
Folliculitis
Infl or inf of hair follicle
If deeper: furuncle or hair follicle abscess
Furuncle may dissemin to adj follicles: carbuncle
RF: DM or Isuppression; eosinophilic folliculitis in AIDS
Dg: clinical; KOH prep/biopsy if fungus or eosinophilic foll
Pseudo aerug: hot tob folliculitis
ttt: topical AB (mupirocin) for mild superf; oral cephalexin or cloxacillin if severe; clindamycin if MRSA
Acne vulgaris (PE)
Hormonal activ of sebaceous glds; Propionibacterium acnes
Etiologies: medic (lithium/CS), occlusion (cosmetics)
Puberty + several years
3 stages: comedonal (open/blackH; closed/whiteH); inflamm (comed rupture, papul/pust/nod/cyst); scar
Severe cystic acne (esp male ado)
Women 20s: cyclic flares, fewer comedones, esp chin
Acne vulgaris (dg, ttt)
Dg: clinical
ttt:
Mild/moderate: topical retinoids #1 (comed acne); topical benzoyl peroxide (kills Prop.acnes). If inadeq, add topical AB (clindamycin, erythromycin)
Moderate-severe: topical ttt + oral AB (doxycycline, minocycline). If all fails, oral retinoids (isotretinoin) but stop all other ttt and OCPs + periodic check LFTs, choles, Tg
Pilonidal cysts (PE, RF)
Abscess in sacrococcygeal region/natal cleft
Folliculitis → abscess→ inf (perineal bugs, Bacteroides)
Esp 20-40yo male
Tender, fluctuant, warm +/- purulent drainage, cellulitis
RF: deep hairy natal cleft, obesity, sedentary
Pilonidal cysts (dg, ttt)
Dg: clinical
ttt: incision + drainage then sterile packing of wound
Local hygiene/shaving (prevents recurr)
AB just if cellulitis (aerob + anaerob coverage)
Tinea versicolor
Malassezia furfur, yeast of normal skin flora
RF that turns it pathogenic: humid, sweaty, oily skin, cushing sd, Isuppr
Small scaly patches, pink/hypo/hyperpigm, chest/back
Dg: clinical; KOH prep (spag+meatb)
ttt: topical ketoconazole or selenium sulfide
Candidiasis (PE)
Any C, esp C albicans
Icompet: superficial inf skin/mucous where moist (groin/skin folds/axillae/vagina/below breast)
Infant/Isuppr: oral thrush; diaper (infants)
Hx: AB, steroid, DM, Icompr
Skin: erythem patches, small satellite lesions
Candidiasis (dg, ttt)
Dg: clinical; KOH prep (spores, pseudohyphae); culture (accurate)
ttt:
Oral inf: oral fluconazole, nystatin S/S, clotrimazole troch
Superficial: topical antifung + clean/dry skin
Diaper: topical nystatin
Dermatophyte infections
Tissues w/ keratin (skin, nails, hair)
Trichophyton, Microsporum, Epidermophyton
RF: DM, ↓periph circul, Icomprom, chronic maceration (athlete)
Dg: clinical; KOH (hyphae); culture (accurate)
ttt: topical antifungals; oral if spread/unresp
T.capitis / Icompr: oral ttt to penetrate hair follicles
Dermatophyte infections (4 subtypes)
Tinea corporis: scaly pruritic, sharp irreg border, central clearing
Tinea pedis/manuum: chronic interdig scaling or on soles
Tinea cruris: groin
Tinea capitis: scalp, scaling, hair loss; keroin (if large)
Lice (PE)
Live off blood; secrete toxins → severe pruritus
Part dep on species: head, body, pubic
Body contact; sharing cloth, hair access
Inadeq hygiene, crowded living
2* bact inf (after pruritus, excoriation)
Lice (dg, ttt)
Dg: see lice or eggs on hair/cloth
ttt:
Head L or Pubic L: topical permethrin, pyrethrin, benzyl alcohol, mechanical removal
Body L: wash+++ body/cloth/bedding
Scabies (PE)
Sarcoptes scabiei burrow into epidermis → pruritus
Close contact
2* bact inf (scratching)
Intense pruritus esp night, after hot shower
Erythem papul, linear tracks
Skin folds of hand, wrists, axillae, genitals
Scabies (dg, ttt)
Dg: Hx of pruritus in several fam mmbers
Scraping tunnel + microsc
ttt: 5% permethrin from neck down (head/toe: infants) + ttt surrounding; or oral ivermectin; wash everything
Decubitus ulcers
Continuous pression on skin → restrict microcircul → ischemic necrosis
RF: bedridden ptts, underlying bony promin+lack of fat (sacrum/fat); incontin urine/stool macerate skin
Dg: clinical
ttt: #1 prevention (move ptts, special bed); routine wound care+hydrocolloid dressing (if low-grade); surgical debrid (if high-grade)
Gangrene
Necrosis of body tissue: wet, dry, gas
Dry: by insuff bld flow to T (atheroscl); dull ache, cold, pallor; toes/fingers bluish-black. RF: DM, vasculopat, smoking
Wet: bact inf (w/ skin flora); bruised, swollen, blistered w/ pus
Gas: Clost perfringens inf; site of large trauma/surgery, comprom bld flow → anaerobic env.; bact destroy T; dirty wounds; !medical emergency
Gangere (dg, ttt)
Dg: clinical; X-ray (air in soft T)
ttt: surgical debrid (+/- amputation) + AB
Hyperbaric O2 (toxic to C.perfr) after debrid helps
Acanthosis nigricans
Hyperkeratotic + hyperpigmented skin; velvety app Intertriginous zones (neck, genitals, axillae)
Ass w/ DM, Cushing ds, PCOS, obesity, paraneopl (GI adenoK)
ttt: not ttt; encourage weight loss
Lichen planus
Self-lim, recurr, chronic infl
Skin, oral mucosa, genitalia
Etiologies: drugs, HCV inf
6 P’s: planar/purple/polygonal/pruritic/papules/plaques
Wickham striae (white lines), Koebner phenomena (at site of trauma)
ttt: topical CS (mild); systemic CS + phototherapy (severe)
Rosacea
Chronic disorder of pilosebaceous units; unclear etiology
Middle-age, fair skin, esp female
AbNl flushing after hot drinks/spicy food/alcohol/sun
Early: central facial erythema w/ telangiectasias
Later: papules, pustules
Longstanding: rhinophyma
Ocular rosacea → blepharitis, stye, chalazion
ttt: topical metronidazole; oral doxycycline (if severe or ocular)
Pityriasis rosea
Acute dermatitis; unknown etiology
Reaction to viral inf w/ HHV-7
Herald patch (erythem w/ periph scale) → multiple scaling papul/plaq w/ fine scale; Christmas tree pattern
Dg: clinical; confirm w/ KOH prep (r/o fungal inf)
ttt: rash heals 6-8wks w/o ttt; support ttt w/ lubrication, antipruritics, antihistamines
Vitiligo
Acquired loss of fction or absence of melanocytes
2* to autoimmune ds (serologic markers of AI ds)
Sharp demarcated depigmented macules/patches
Hands/face/genitalia
ttt: topical steroids, tacrolimus ointment, UV, laser
! Sunscreen prevents burns
Eyelid lesions
Xanthelasma: soft yellow, medial, bilat; ass w/ hyperlipidemia and 1* biliary cirrhosis
Hordeolum: painful acute gland inf (stye); S aureus; edge
Chalazion: chronic infl painless cyst; blocked gland
Seborrheic keratosis
Skin tumor; No malignant potential
Almost every person >40yo
Exophytic, waxy brown, superf keratin cysts
Dg: clinical (#dg melanoma)
ttt: cryotherapy, shave excision or curettage
Actinic keratosis
Erythema, scale, flat; by sun exposure
ttt to prevent transfo to SCC
Face/arms, older ptts, multiple lesions
Dg: clinical
ttt: cryosurgery, topical 5-FU, topical imiquimod
If carcinoma susp: biopsy then excision/curettage
! Sunscreen
Cutaneous squamous cell carcinoma (RF, PE)
2 skin cancer; locally destructive; mets/death
RF: sun expo, chemical carcinogens, radiation therapy, burns, chronic trauma, Isuppr
Esp older ptts, sun-dam skin, after actinic keratoses
Erythem ulcerated papul/nodul
Marjolin’s ulcer: rare type in site of scars/burns/ulcers
Palmoplantar distrib: arsenic expo
SCC that arise on lips/ulcers: ↑R of metast
Cutaneous squamous cell carcinoma (dg, ttt)
Dg: clinical; confirm w/ biopsy
ttt: surgical excision or Mohs surgery
If high metast potential: radiation or chemotherapy
Basal cell carcinoma
1 skin cancer; slow, locally destructive; No metast
RF: cumulative sun expo
Sun expo areas; if on non-sun-expo + early in life, inherited basal cell nevus sd
Many types, degrees of pigm/ulceration/depth of growth
Nodular, superficial, sclerosing
Dg: clinical; confirm w/ shave biopsy
ttt: excision via curettage/cautery/cryotherapy/superf radiation; and Mohs surgery
Melanoma (RF)
#1 life-threatening dermato ds RF: fair skin, tendency to burn; intense bursts of sun expo; large congen melanocytic nevi, ↑nb of nevi, dysplastic nevi; Icomprom Familial atypical mole and melanoma (FAM-M) sd (predisp)
Melanoma (dg)
Begin in epidermal basal layer (melanocytes); metast
! early dg + ttt
Malignancy determ by histo
Screen: ABCDE (Asym, irreg Border, variat* Color, Diameter >6mm, Evolution (pruritus, new lesions)); dermoscopy
Excisional biopsy on any susp lesion
Stage: Breslow thickness and TNM
Melanoma (ttt)
Confined to skin: excision w/ margins; sentinel LN biopsy for staging
If recurr/metast: chemoTh, radiationTh
Early melanoma: ↑R of subsequent melanomas
Late melanoma: ↑R of recurr or metast (! surveillance)
Ulceration: poor prognosis
5 types of melanoma
Superficial spreading: 60%; any age; trunk men; legs women; early dg; slow horiz growth
Nodular: rapid vertic growth; reddish-brown nodule w/ ulceration
Acral lentiginous: palms/soles/nailbed; slow; asians/blacks
Lentigo maligna: solar lentigo; on sun-dam skin of face
Amelanotic: w/o pigmentation; from any of other types
Kaposi sarcoma
Vascular prolif ds; HHV-8
Multiple red/violac macules/papul/nodul then plaques
Lower limbs, back, face, mouth, genitalia; GI, lungs
HIV-ass KS: aggressive
Dg: Hx, clinical, histo
ttt: HAART if HIV+; radiation of cryotherapy (if small); systemic chemotherapy (if spread/internal) as Doxorubicin, paclitaxel, IFN-alpha
Mycosis fungoides (cutaneous T-cell lymphoma) (PE)
Slow, progress, neoplast prolif of T cells
Chronic; esp men
Early: pso-app plaqu/patch, pruritic; trunk, butt
Later: skin tumors w/ palpable LN
LN, spleen, liver involvement
Sezary sd: leukemic phase of cutan T-cell lymphoma
Mycosis fungoides (cutaneous T-cell lymphoma) (dg, ttt)
Dg: clinical and histo; immuno charact; e- microscopy (Sezary or Lutzner cells = cerebriform lymphocytes) #dg: dermatitis. So every chronic/resistant dermatitis should have histo
ttt: phototherapy; steroids; chemoTh; retinoids; monocl Ab; IFN
Localized: total skin electron beam irradiation
Extensive/Advanced: radiation therapy
Cherry angiomas (hemangiomas)
1 benign vascul tumor
Small vascular red papules
Anywhere; ↑ w/ age
No ttt
