Derm Flashcards
Macule Papule Patch Plaque Vesicle Bulla
Flat lesion < 1cm Raised lesion < 5mm Macule > 1cm Papule >5mm Fluid filled lesion < 5mm Vesicle > 5mm
Type 1 hypersensitivity names, path, examples*,
“Anaphylaxis, atopic” “IgE mediated”
Preformed IgE antibodies on MAST/basophils react to antigen ==> fast, massive vasoactive amine release
Anaphylaxis
Asthma
Hives 2/2 drug reactions
Type 2 hypersensitivity names, path, examples*
“Cytotoxic” “Antibody mediated”
IgM/IgG and complement form membrane attack complex ==> cell lysis
Goodpasture’s
Autoimmune hemolytic anemia
Erythroblastosis fetalis
Rheumatic fever
Type 3 hypersensitivity names, path, examples*
“Immune complex”
Antigen-antibody ==> complement ==> PMNs
SLE, glomerulonephritis, RA, polyarteritis nodosa
“Serum sickness”
Antibodies form over ~5 days ==> immune complexes form and lodge in membranes ==> complement fixation ==> tissue damage
Drug reaction
“Arthus reaction”
Preformed antibodies ==> vascular necrosis
2/2 vaccines
Type 4 hypersensitivity names, path, examples*
“delayed / cell mediated”
Sensitized T-lymphocytes release cytokines ==> macrophage damage (no antibody damage)
Transplant rejection
Contact dermatitis
Tb skin test
Atopic dermatitis / eczema path, presentation, dx, tx
Type 4 (?) skin rxn 2/2 many triggers (nickel, plants, emotional, climate etc.)
Presents different in different age groups**
- Infants: SYMMETRIC, erythematous, edematous, pruritic papules on face, scalp, chest, & EXTENSOR surfaces
- adolescents: dry, scaly, red papules on FLEXOR and neck
- adults: lichenification on FLEXOR surfaces, eyelids, hands
Eosinophilia & IgE elevation
Moisturizers ==> topical steroids ==> tacrolimus [2wks maximum]
Erythema toxicum neonatorum presentation, dx, tx
Blanching papules
1-3 days post delivery
SPARING PALMS/SOLES
Clinical
Eosinophila
Benign: no tx
Contact dermatitis path**, presentation, dx, tx
Type IV hypersensitivity reaction (requires prior exposure ==> T-cell activation)
Red, edematous, vesicles/papules often in distribution of offending agent
Clinical dx
Patch testing can identify agent
Topical steroids
Eczema herpeticum path, presentation, dx, tx*
Systemic HSV infection 2/2 eczema (aka atopic dermatitis)
Infant with atopic dermatitis history
Numerous vesicles and erythema over area of previous dermatitis
FEVER, adenopathy
Clinical
IV acyclovir STAT!
Seborrheic dermatitis path, presentation*, dx, tx
Pityrosporum ovale yeast dermatitis with propensity for sebum & hair follicles
Infants: cradle cap (yellow scale on scalp)
Other: red-yellow, oily, scaly patches on ears, eyebrows, nose, scalp
*Common in Parkinson’s and AIDS patients
Dx: r/o contact dermatitis and psoriasis
Tx:
- babies: routine bathing
- adults: zinc pyrithione or selenium sulfide shampoos; topical antifungal or corticosteroid
Psoriasis path, presentation, dx, tx
T-cell inflammation in dermis ==> epidermal hyperplasia
Begins in teens, early adulthood
Red plaque, sharp demarcations, with SILVERY scale
EXTENSOR surfaces
Nail changes: oil spots, pitting, lifting
Auspitz’ sign: bleeding when scraped
Biopsy: thickened epidermis with preserved nuclei (parakeratosis) in stratum corneum (outermost epidermis) and neutrophilic inflammation; elongated rete ridges
Topical steroids
Keratolytic agents: tar, UV light
Vitamin D3
Methotrexate if severe
Urticaria (hives) path, presentation, dx, tx
Type 1 hypersensitivity reaction of MAST cell histamine & prostaglandin release
Rapid onset hives…
Clinical
Antihistamines
IM epinephrine
Airway management
Drug eruption path, presentation, dx, tx
Types 1-4 hypersensitivity…could be any!
Usually 7+ days post-drug…so unlikely if 1-2 days after starting new drug
Symmetric, pruritic rash
Eosinophilia
Remove drug
Topical steroids & antihistamines
Erythema multiform “minor” (EM) path, presentation*, dx, tx, risks
Often 2/2 HSV or mycoplasma
Red, target-shaped lesions
+/- MINOR constitutional symptoms
PALMS/SOLES
Clinical
Symptomatic tx only… no steroids needed
Risk ==> progression to SJS or TEN (share single disease spectrum)*
Stevens-Johnson Syndrome (SJS, EM “major”) / Toxic Epidermal Necrolysis (TEN) path, presentation, dx*, tx
Immune-complex mediated hypersensitivity ==> exfoliating skin, often 2/2 erythema multiform or drugs: phenytoin, carbamazepine, penicillin, sulfonamides (TMP-SMX), allopurinol, NSAIDs
SJS < 10% BSA
-same targetoid lesions as EM minor, but more prominent in mucosal and widespread lesions
-more prominent constitutional symptoms than EM minor
TEN > 30% BSA
Massive mucocutaneous rash
Often targetoid lesions
Genital involvement
+ NIKOLKSY SIGN: sloughing with light touch
Biopsy:
- SJS = basal epidermis degeneration
- TEN = eosinophilic full thickness epidermal degeneration
Tx: systemic corticosteroids, IVIG
Erythema nodosum path, presentation, dx, tx
Panniculitis of legs, usually 2/2 infection, drugs, chronic inflammatory diseases
Painful pretibial nodules
Clinical dx
False + VDRL (like SLE)
Remove underlying cause or workup for trigger disease
Bullous pemphigoid path, presentation, dx, tx
Anti-bullous pemphigoid antigen and/or IgG & C3 attacking hemidesmosomes at BM dermal-epidermal junction
> 60 y/o
Tense, independent vesicles / bullae
Usually NOT mucosal
NEGATIVE Nikolsky’s sign
Clinical
Immuno: IgG and C3 deposits at dermal-epidermal junction
Prednisone
Pemphigous vulgarism path, presentation, dx, tx
Anti-desmoglein antibody (IgG) destroys keratinocyte adhesion WITHIN epidermis, often 2/2 drugs: ACEi’s, penicillamine, penicillin, phenobarbital
40-60y/o Confluent, scaly erosions Usually mucosal involvement \+Nikolksy sign More severe course than BP
Clinical but biopsy can be used
High dose prednisone + IVIG etc.
HSV 1&2 path, presentation**, dx, tx
Dormant in nerve ganglia but infect epidermal cells causing fusion of epidermal giant cells
Herpes…painful lesion of lips & genitals
Herpetic whitlow: swollen herpetic lesion on hand 2/2 genital herpes or contact with saliva (dentists…)
Biopsy: multinucleated giant cell on Tzank smear (doesn’t r/o VZV)
Acyclovir (IV if severe)
Dermatitis herpetiformis path, presentation, dx, tx
Celiac-related
Celiac hx
Pruritic papules and vesicles occurring bilaterally along elbow, knees, butt, neck, scalp
Immunoflouresence: IgA deposition at dermal papillae
Dapsone* + gluten free
Varicella zoster path, contagiousness, presentation, dx, tx
VZV…aka chicken pox
Passed via droplet or direct contact
10-20 day incubation
Contagious 24 hours pre-manifestation until lesions crust
Constitutional symptom prodrome
Pruritic rash anywhere EXCEPT palm/soles
Clinical
Self-limited
Herpes zoster path, presentation*, dx, tx
VZV recurrence in a nerve (aka shingles)
Painful prodrome ==> dermatomal papules evolving into vesicles & bullae ==> crusting in 10 days
*Most common in immunocompromised and elderly
Clinical dx
-cyclovir & pain control
Molluscum contagiousum path, contagiousness, presentation, dx, tx
Poxvirus* in children or HIV/AIDS immunocompromised spread by direct contact
Waxy, flesh-colored papule with central umbilication usually on trunk, limbs, anogenital area
Clinical but also express fluid onto slide to find inclusion or molluscum bodies
Physical destruction with freezing or acid
Warts / verrucae path, presentation, dx, tx
HPV via direct contact
16 & 18 can cause squamous malignancy
Cauliflower-like or velvety white lesion
Clinical
Genital: cryotherapy
Cervical: pap smear ==> colposcopy
Impetigo path, presentation*, dx, tx
Group A staph or strep skin infection
Common: macule ==> pustule ==> pops into honey color crusting, usually on face
Rare: bullous type on extremities, usually 2/2 S. aureus and can cause scalded skin syndrome (SSS)
Clinical
Topical antibiotic with staph/strep activity, like mupirocin
Scarlet fever path, presentation*, dx, tx
Strep pyogenes
Preceded by throat infection ==> fever, vomiting, headache ==> upper body papules with sandpaper texture
Strawberry tongue
Penicillin
S. typhi presentation dx, tx
Triad:
Truncal papules > 10
Fever
GI involvement
Floroquinolone + 3rd gen cephalosporin
Cellulitis path, presentation, dx, tx
Staph or group A strep ==> infection of skin & subQ
Hot, swollen, tender skin
Clinical, but culture for MRSA
Oral abx UNLESS: systemic signs (high fever, chills etc.), diabetic, hand or orbital involvement, old/young ==> IV nafcillin, cefazolin, vanc
Necrotizing fasciitis path, presentation*, dx, tx
Strep pyogenes, staph aureus, E. coli, clostridium perfringens ==> infection of fascial plane
Often 2/2 trauma or surgery Severe pain Putrid discharge Bullae Gas production Rapid erythema
XR or CT: gas in lesion
Biopsy @ edge of lesion: diagnostic
Emergent surgery
Penicillin G, if Strep
Metronidazole or 3rd gen cephalosporin if anaerobic
Fournier’s gangrene
Necrotizing fasciitis of balls!
Acne vulgaris path, presentation, dx, tx**
Hormone activation of sebaceous gland ==> comedone plugs ==> inflammation 2/2 Propionibacterium acnes
Blackhead/whitehead ==> topical tretinoin or benzoyl
Inflammatory ==> topical benzoyl + tretinoin ==> topical erythromycin ==> systemic erythromycin or tetracycline
Severe ==> oral isotretinoin (must check triglycerides, cholesterol, LFTs, and beta-HCG monthly)
Tinea versicolor path, presentation, dx, tx
Fungal skin infection 2/2 Malassezia furfur
Hypo or HYPERpigmented skin lesions, often post-humid climate
SCALE with scraping though don’t appear scaly
KOH prep: spaghetti & meatballs hyphae and spores
Tx: ketaconazole or selenium sulfide
Candida path, presentation, dx, tx
Candida fungus ==> oral or skin infection
Recent abx, steroids, DM, or HIV
Mouth: white lesions that DON’T scrape
Skin: erythematous patches with satellite lesions
KOH prep showing hyphae and psuedospores
Oral: oral fluconazole & nystatin wash
Skin: topical fluconazole or nystatin
Dermatophyte path, presentation, dx, tx*
Fungi? Microsporum and Trichophyton
*Tinea corporis: red, scaly, pruritic, central clearing, well-circumscribed often in children or immunocompromised
Tinea pedis: athletes foot
Tinea cruris: jock itch
Tinea capitis: similar to seborrheic dermatitis
KOH prep showing hyphae
Antifungal: terbinafine*, itraconazole, griseofulvin
Lice path, presentation, dx*, tx
Parasite of hair, skin, or pubes (“crabs”)
Intense itching
Visible on CLOTHES, not people
Pyrethrin or permethrin (“RID”) + ETOH wash
Scabies path, presentation, dx, tx
Arthropod burrows into skin and forms tunnels
Intense itching, especially at night and after hot showers
Vesicles with linear track (burrowing), especially hands between knuckles and genitals
Clinical / visible
Permethrin or ivermectin
Gangrene path, presentation, dx, tx
Dry: vascular insufficiency ==> cold, blue
Wet: bacterial infection ==> bruised & pustulent
Gas: C. perfringens ==> pale / red 2/2 trauma
AMPUTATE
Abx are given but only to preserve healthy tissue
Hyperbaric O2: kills anaerobic Clostridium
Acanthosis nigricans presentation, associations
Dark hyperkeratotic skin under arms, genitals
2/2 DM, PCOS, cushing, obesity, or PARANEOPLASTIC GI malignancy in older people
Lichen planus path, presentation, dx, tx
Inflammatory dermatosis
Flat topped, violaceous, polygonal plaque often @ trauma site
Steroids
Rosacea presentation*, dx, tx
Facial erythema and telangiectasias in middle aged folk, usually those who flush easily
Precipitated by hot/cold, emotion
Topical metronidazole ==> daily doxy
Pityriasis rosea path, presentation, dx, tx
Unclear but perhaps 2/2 human herpes virus
Often young adults
Herald patch: initial oval plaque ==> progresses to truncal oval plaques with fine “cigarette paper” scaling, often in christmas tree pattern on back
Clinical: r/o Tinea corporis with KOH
Self-limited but antipruritics help
Seborrheic keratosis path, presentation*, dx, tx
Unknown etiology
Stuck-on, crusty brown-blue lesions
Clinical
Cryotherapy, 5FU
Actinic keratosis path, presentation*, dx, tx
Pre-malignant squamous cell carcinoma
Red with white, “sandpaper” scaly plaque on sun-exposed area
Biopsy to r/o SCC? ==> cryotherapy, topical imiquimod or 5-FU
Squamous cell carcinoma path, risk factors, presentation, dx, tx
Squamous cord with keratin pearls in vermillion zone
Sun exposure = #1
ARSENIC exposure on hands
Chronic trauma (non-healing lesions should be suspected*)
Ulcerating, crusting plaque
Often on lip
Biopsy ==> excise
Basal cell carcinoma path, commonality, risk factors, presentation, dx, tx
Spindle cells with palisaded basal cells
Most common skin cancer ==> locally destructive but no real metastatic potential
UV light
Waxy, rolling border with telangiectasias
RARELY if ever on lips
Excision
Melanoma subtypes, dx, tx
Lentigo: arises on lentigo 2/2 sun-damage
Superficial spreading
Nodular: rapid vertical growth, reddish brown
Acral: on hands or feet in patch
Amelanotic
Excisional biopsy to get Breslow depth
If >1mm ==> sentinel node biopsy
Kaposi’s sarcoma path, presentation, dx, rule out, tx
Associated with HSV8 ==> vascular proliferation
Many violaceous plaques
Biopsy & clinical
Rule out: Bartonella infection “bacillary angiomatosis”!
Excision
Mycosis fungoides path, presentation, dx, tx
Cutaneous T-cell lymphoma
Early: psoriatic plaque, non-specific
Late: red-brown nodular tumors and lymphadenopathy
Sezáry cells: cerebriform lymphocytes
Any non-healing dermatitis needs biopsy to rule this out!
Phototherapy
Staph scalded skin syndrome path, presentation, tx
Staph aureus toxin against desmoglein 1
Fever prodrome
Diffuse erythema, starting on face ==> flaccid bullae and perioral crusting
+Nikolsky
Oxacillin or vancomycin
Scary neonatal diseases passed from mom presentation, tx
VZV or herpes
Fever
VESICULAR rash ==> disseminated multi organ failure
Acyclovir!
Sunscreen recommendation
30+ applied 15-30 minutes before going outdoors
Reapply q2 hours
Henoch schonlein purpura (HSP) path, presentation, dx, tx
IgA vasculitis
Tetrad: symmetric LE palpable purpura, abdominal pain (colicky), renal disease (glomerulonephritis), arthralgia
NO THROMBOCYTOPENIA
Often 2/2 recent infection, especially children
Dx: clinically if LE purpura + one of above…or biopsy
NSAIDs & supportive care
Cherry hemangioma path, presentation*
Benign vascular tumor
Sharply circumscribed cherry-looking thing in adults
Rubella other name, path, presentation*, dx, tx
German measles
RNA togavirus 2/2 droplets
Mild fever Pink maculopapular rash initially on face spreading downward & outward Nonexudative conjunctivitis Lasts <3 days Pregnant women: causes miscarriage
Clinical
Supportive care
Measles presentation*
Severe fever
Slowly spreading dark red-brown rash
Mumps presentation*
Low-grade fever
Parotitis
No rash
Infantile hemangioma presentation*
Big strawberry looking hemangiomas on a baby’s ass
Cavernous hemangioma presentation*
Soft blue mass
Cystic hygroma presentation*
Dilated lymph space on neck that transilluminates
Icthyosis vulgaris presentation*
Normal skin at birth progressing to dry, scaly, horny skin over extensor limbs
Chalazion presentation, dx, tx
Painful swelling progressing to painless rubbery non-red lesion
MUST biopsy…risk of sebaceous gland carcinoma or BCC
Remove
Warfarin-induced skin necrosis presentation, tx
Pain without lesion ==> bullae and necrosis on breasts, butt, thighs, abdomen
Roughly a week post-warfarin
Vitamin K administration
Heparin instead of warfarin
Angioedema path, presentation, dx, tx
Hereditary or acquired (ACE inhibitor) C1 inhibitor deficiency ==> C2b and bradykinin elevation
Facial, laryngeal, extremity, genital swelling
Colicky abdominal pain 2/2 GI swelling
*No anaphylactic trigger…thus no tachycardia etc.
INTUBATE
Graft Versus Host Disease (GVHD) path, presentation
Donor T cells target host skin, GI, liver
Face, PALM, SOLE rash
GI sx: +blood
Liver: LFTs elevation & jaundice
Porphyria cutanea tarda path, presentation*, dx, tx
Deficiency of uroporphyrinogen decarboxylase
Painless blisters and skin fragility on dorsal hands
Hyperpigmentation of face
Associated with Hep C (?)
Elevated urinary porphyrin
Phlebotomy
Hydroxychloroquine
Vitiligo path, presentation
Autoimmune melanocyte destruction
Associated with: pernicious anemia, DM1, alopecia, autoimmune thyroid etc.
Depigmentation beginning peri-orally and acridly
Erysipelas path, presentation*, tx
Strep
Patch ==> raised, tense, indurated plaque
Usually on cheek
2/2 trauma or pharyngitis
Penicillin
Senile purpura path, presentation
Loss of vascular connective tissue elasticity in elderly
Echymoses
Normal heme labs
