Dermatology Flashcards
Parvovirus causes…
Fifths disease aka erythema infectiosum
CP: Fever, HA, maculopapular rash (lacy reticular pattern) on back & abd (recurs with heat/sunlight) & “slapped red cheeks”
Tx = symptomatic
Prog = self limiting with excellent prognosis
Parvo-virus - 5 letters & = fifth disease
Coxsackie virus causes…
Hand foot & mouth disease
Poxvirus causes…
Molluscum contagiosum & other diseases - 9 different pix viruses
SARS is caused by…
Coronavirus
All ages
CP: Atypical one
Koebner’s phenomenon - what is it? What diseases does it happen in?
New lesions at site of trauma
Seen in psoriasis and lichen planus
Wickham straie
Fine white lines on the skin lesions or on the oral mucosa of people w/ lichen planus
Salmon-colored papule with white colarette scaling along cleavage lines
Pityriasis Rosea
Confined to trunk & proximal ext, face spared
Pityriasis rosea - thought to be idiopathic but has some relation to which infection?
viral infections, especially human herpes virus 7 (HHV7)
Pustular psoriasis - MC location, description
Location
Description
A/w?
Deep, yellow, non-infected pustules that evolve into red macules on palms/soles
Most severe variant (von Zumbusch type) – can be deadly. Acute onset widespread erythema, scaling, sheets of superficial pustules (WHOLE BODY). Assoc w/ systemic symptoms: malaise, fever, diarrhea, leukocytosis, hypocalcemia. Caused by: pregnancy, infection & withdrawal of glucocorticoids.
FAM HX of psoriasis (genetic component) - 2/2 keratin hyperplasia cells in the stratum basale due to T-cell activation & cytokine release
Guttate psoriasis
Location
Description
A/w?
Small, erythematous papules with fine scales, discrete leisons & confluent papules
Trunk & extremities most affected. Child/young adult w/ no hx psoriasis. Strong assoc w/ recent strep infection.
Plaque psoriasis
Location
Description
A/w?
Most common variant (>50%), symmetrically distributed cutaneous plaques on scalp, extensor elbows, knees & gluteal cleft – may be asymptomatic, pruritis common
Inverse psoriasis
Location
Description
A/w?
Inverse p = intriginous areas affected (inguinal, perineal, genital, intergluteal, axillary, inframammary), D/dx = fungal/yeast/bac inf under breast folds – given anti-fungal, not better, come back = inverse psoriasis
Erythrodermic psoriasis
Uncommon, acute or chronic, generalized erythema/scaling head to toe (whole body), complications = loss of adequate skin barrier (first line innate immune defense → abscess, cellulitis) & electrolyte abnl). NOvesicles/pustules.
Psoriasis is called a multi-systemic disease - Which other systems are involved frequently?
Nail beds - nail pitting
Joints - psoriatic arthritis - rheum issue
Mild to moderate psoriasis treatment
Mild to Moderate:
Emolients (like eucerin) to keep skin moist
Topical corticosteroids - HIGH DOSE
Hydrocortisone, Triamcinolone, fluocinonide, betamethasone dipropionate, clobetasol
Alternatives:
Vitamin D analogs → calcitriene, calcitrol, tacalcitol)
Tar-T/Gel, Topical retinoids, anthralin shampoo, tacrolimus or pimecrolimus for face
Moderate to severe psoriasis treatment
Moderate to Severe Disease:
Phototherapy (good for widespread disease), UVB (alone or w/ topical tar), Narrow band UVB @ sub-erythrmogenic doses, home phototherapy UVB machines
Systemic for severe → Methotrexate, Cyclosporine, Apremilast Biologics (TNF-alpha inhib) Entarecept, Infliximab, Adalimumab, Ustekinumab, secukinumab, ixekizumab, brodalumab, guselkumab
Pityriasis (tinea) versicolor etio
KOH?
Woods lamp?
Tx?
Malassezi furfur (part of normal skin flora)
KOH - spagetti & meatball from hyphae & spores
Woods lamp - yellow-orange fluorescence
Tx - topical anti-fungal (selenium sulfinde, sodium sulfacetamide, “azoles”
Tx options seborrheic dermatitis, textbook description
“Erythematous plaques with fine white scales” over areas of high sebaceous gland secretion (nasolabial fold, forehead, beard muscache, eyelids, chest, scalp (dandruff)
Tx: Topical selenium sulfide, sodium sulfacetamide, ketoconazole, or ciclopirox, steroids
Type I hypersensitivity reaction
IgE mediated reaction - Immediate
Ex: urticaria, angioedema, bronchospasm, hypotension, anaphylaxis
Type II hypersensitivity rxn
Cytotoxic, antibody-mediated (drugs in combination with cytotoxic antibodies cause cell lysis)
A type II hypersensitivity is said to occur when damage to the host tissues is caused by cellular lysis induced by the direct binding of antibody to cell surface antigens. While the antibodies involved in type I HS are of the IgE isotype, those involved in type II HS reactions are mainly of the IgM or IgG isotype.
Ex - Autoimmune hemolytic anemia, Immune thrombocytopenia, neutropenia
Ab = CELL destruction - why examples are low CELL counts
Type III hypersensitivity reaction
Type III hypersensitivity occurs when there is accumulation of immune complexes (antigen-antibody complexes) that have not been adequately cleared by innate immune cells, giving rise to an inflammatory response and attraction of leukocytes. Such reactions may progress to immune complex diseases.
Examples - Drug-mediated vasculitis Serum sickness Arthus reaction Reactive arthritis IgA Berger, HSP PSGN
Type IV hypersensitivity reaction
Type IV hypersensitivity is often called delayed or cell-mediated hypersensitivity
This is because antigen exposure activates T cells, which then mediate tissue injury. Depending upon the type of T cell activation and the other effector cells recruited, different subtypes can be differentiated (ie, types IVa to IVd).
Ex: Erythema multiforme
Allergic contact dermatitis, some morbiliform reactions (erythema multiforme), severe exfoliative dermatoses (SJS/TEN), DRESS, AGEP, interstitial nephritis, drug-induced hepatitis etc
Types of hypersensitivity reactions
● Type I – Immediate in onset and caused by immunoglobulin (Ig)E-mediated activation of mast cells and basophils
● Type II – Delayed in onset and caused by antibody (usually IgG-mediated) cell destruction
● Type III – Delayed in onset and caused by immune complex (IgG:drug) deposition and complement activation
● Type IV – Delayed in onset and T cell-mediated
Erythema multiforme
Causes Type of rxn A/w? CP Tx
Acute, self-limited type IV Hypersensitivity rxn
Lesions evolve over 3-5 days, last 2 weeks
MC in young adults 20-40 YO
A/w HSV (MC), mycoplasma, S. pneumo, DRUGS (sulfa, BL, phenytoin)
CP:
TARGET (iris) lesions that are dull, “dusty-violet” red purpuric macules/vesicles or bullae in the CENTER surrounded by pale edematous rim & a peripheral red halo
EM minor - NO mucosal membrane lesions . Lesions distributed acrally (peripherally).
EM major - involves > 1 mm (oral, genial ocular) - cover more central BSA, NO epidermal detachment
Tx:
Symptomatic, d/c offending drug, antihistamines, analgesics, topical steroids, oral STEROIDs if severe
SJS/TEN occurs most commonly after ?
Sulfa and anticonvulsant meds, nsaids, allopurinol
SJS - what percent body surface area sloughs off vs TEN?
SJS < 10%
TEN > 30% +/- skin necrosis
Clinical manifestations SJS/TEN
Fever
URI sx
Widespread blisters begin on trunk/face
Erythematous/pruritic macules > 1 mucous membrane involvement with epidermal detachment (+Nikolsky’s sign)
Tx: like severe burns - burn unit admission, pain control, stop offending med, fluid & electrolyte replacemet, wound care
Thrombosed capillaries are pathognomonic for what skin lesion?
Verruca vulgaris (common wart) Verruca plantis (plantar wart)
55 YO male comes in concerned about 10 mm velvety warty plaque on his back - what is most likely dx?
Seborrheic keratosis = “Seb ker”
Also described as a “greasy, stuck-on” appearance sometimes
I think they look warty but book also describes them as “velvety” as the front of this card.
MC in fair-skinned elderly w/ prolonged sun exposure.
Non-bullous Impetigo etio, tx
STAPH
Tx: Mupirocin topical TID x 10 days or if extensive - dicloxacillin
Bullous impetigo
Staph
Ecthyma = only one where GABHS more prominent –> others (bullous, non-bullous are STAPH predominant)
Same tx as non-bullous - topical mupirocin but if extensive disease, dicloxacillin
Ecthyma - etio, description
strEp (GABHS), rare
Causes ulcerative lesions that extend thru epidermis to deep dermis = PUNCHED out ulcers w/ yellow crusts
Treated with ORAL abx if extensive - dicloxacillin
MCC follitulitis, tx
STAPH
Tx: Topical mupirocin, or topical clinda
Furuncle
Deeper infection of the hair follicle (like a bad folliculitis - which is superficial)
Tender nodule with fluctuant abscess with central plut - may have surrounding cellulitis
Management: I&D, heat compresses, oral abx if a/w cellulitis
Carbuncle
Even larger, more painful, interlocking furuncles / abscesses with multiple openings _ cellulitis
Management: I&D, heat compresses, oral abx if a/w cellulitis
Cellulitis - depth in skin, etio, occurs when?, description/CP,
Infection of the DEEP dermis / SQ fat
DX - clinical exam
No well-defined borders, indolent onset, with or without purulence, rubor, warmth +/- lymphangitic spread (lymphangitis) = sign of impending bacteremia
vs. Erysipela - Acute onset of sx, distinct clear borders (well-demarcated), VERY RED, sys sx common (fever, chills)
Erysipelas - etio, description,
Starts w/ E, dute to strep - GABHS MCC
WELL - DEMARCATED margins, SUPER red, MC on face
Tx: IV Penicillin
Vs cellulitis - No well-defined borders, indolent onset, with or without purulence, rubor, warmth
Tx: Usually oral Keflex x 1 week. Clinda if PCN allergic. + MRSA, covered w/ bactrim, clinda orally but IV vanc if really sick
Cat bite - etio, tx
Pasturella - Augmentin!
Dog bite - etio, tx
Capnocytophaga canimorsus
Augmentin
Human bite - etio, tx
Anaerobes, mouth flora
Augmentin
Paronychia - etio
Staph
Felon
Closed space infection of hte finger pulp - must do I&D w/ abx
Scabies - CP, tx
Burrows in web spaces - intense pruritis, increased at night - spares the neck & face - likes warm areas
OR - red itchy pruritic papules on scrotum, glans or penile shaft, body folds = pathognomonic for scabies
Tx = Permethrin - apply cream to entire body, then repeat 1 week later
Think - ppl who do meth think they have scabies & itch all over - tx = perMETHerin (same with lice)
Pediculosis (lice)- CP, tx
Intense itching in HEAD/occipital area
CP: Nits in hair - white oval shaped egg capsules at hte base of hair shafts - removed w/ a comb
Tx = permethrin - for head = shampoo, if in pubic hair then permethrin lotion
Bedding & clothing laundered in HOT water w/ detergent & drier in hot drier for 20 + minutes
Toys that can’t be washed - place in air-tight plastic bag x 14 days
Molluscum description, tx
Description: single or multiple dome-shaped, flesh-colored to pearly-white, waxy papules w/ CENTRALUMBILICATION
No tx needed in most cases (resolve on own in 3-6 mo) or can use cryotherapy, curettage etc
Tinea capitus - description, tx
Varied presentation - annular, scaling lesions, broken hair shafts. Inflamed plaques with multiple pustules with scarring & alopecia - “ring worm” = the common name
Tx: PO GRISEOFULVIN
**Note: all other dermatophyte infections (tinea barbae, tenia pedis, tineacruris, tinea corporis) first line is TOPICAL antifungal creams but the scalp is too thick & so you need an ORAL antifungals as first line
How do you tell apart erythema multiforme from tinea corporis?
Tinea corporis has SCALE
Erythema multiforme does not
Etiology of tinea infections, dx
AKA dermatophyte infections
Casused MC by trichophyton, microsporum
Dx: KOH, woods lamp
Notes:
If caused by microsporum then it glows green under woods lamp
Tinea versicolor = yellow- orange under woods lamp.
Normal skin = BLUE
Pemphigus Vulgaris - patho, description, dx, tx
Gus is 30 YO M anti-drone - does’t believe in them & pemphiGUS is AI dz w/ anti-desmosome ab
MC in pt in 30’s - young
CP: Oral mm erosions & ulcerations FIRST, then painful FLACCID skin bullae (rupture EASILY)- leaves painful denuded skin eriosions that bleed easily. + NIKOLSKY SIGN. (b/c desmosomes normally bind keratinocytes together to form the epidermis so your epidermis can’t stay all attached & fluid leaks out = bullae)
Dx: Skin biopsy (intraepithelial splitting with acantholysis), IgG t/o the epidermis. Elisa = anti-desmoglein ab
Tx: HIGH-dose STEROIDS = first line. Methotrexate. Local wound care (like burns)
Bullous pemphigoid
What it is:
Chronic, widespread AI blisterin skin disease of the ELDERLY (65-75 YO)
(AGE = one way to tell apart from pemphigus vulgaris)
Patho: Type II HSN - IgG attacks the epithelial basement membrane causing SUB-epidermal blistering (esp in groin, axilla, abdomen) +/- drug-induced
CP: TENSE bullae - dont rupture easily (unlike pemphigus = FLACCID bullae = rupture easily) NEGATIVE nikolsky sign
Old ppl have lots of growths on them - walking around with tense bullae = new blob growth - wont rupture easily
Tx: Systemic corticosteroids, antihistamines, immunosuppressants = azathioprine
Melasma - what is it, RF, CP, dx, tx?
What: hypermelanosis of sun-exposed areas
RF: Ince estrogen exposure, sun exposure, women w/ darker complexions
Dx: wood’s lamp - appearance unchanged
Tx: Sunscreen, topical bleachers (Hydroquinone)
Brown recluse spider bite - look of spider, location in US, bite reaction, treatment
Brown recluse = Loxosceles RECLUSA. MC in southwest/midwest, has a violin shaped- marking on back
CP: Bite site necrosis. Venom = vasoconstriction = white halo surrounded by erythema –> vascoconstriction = ischemia = necrosis = hemorrhagic bullae that undergoes eschar formation
(Think of whacking violin over your hand super hard = FUCKED up your hand)
Tx: Pain control, Tetanus PPX, local wound care +/- debridement if necrosis. Abx if 2ry infection.
Black widow
Black widow = latrodectus hersperus
CP: Local sx - asx or small amt pain at bite site with SYSTEMIC sx - muscle pain, spasms, rigidity
(Widower will poison you without leaving a trace - systemic sx (muscle pain, spasms, rigidity) but local bite mark = fine)
Tx: MIld - wound care & pain control. Moderate = severe - opioids +/- muscle relaxants (benzos). Antivenom reserved for pt not responsive to above meds. Given after consult w/ toxicologist.
Burns - rule of 9’s
**For second and third degree burns only
Palm ~1% Face/neck 4.5% Chest 9% ABD 9% Genitalia 1% Front of one arm 4.5% Front of one leg 9%
What is considered a MINOR burn?
< 10% TBSA in adults
< 5% TBSA in kids
< 2% full thickness
- Must be isolated injury
- *Must not involve face, hands, perineum, feet
- *Must not cross major joints, no circumferential burns
What is considered a MAJOR burn?
> 25% TBSA in adults
20% TBSA burn in very young or very old
10% full thickness burn
- *Any burn involving face, hands, perineum, feet
- *Burn crossing major joints, circumferential burns
What tx is recommended for circumferential burns? why?
Escharotomy
Prevents compartment syndrome
Tx burns
Topical abx to any nonsuperficial burn. Silver sulfadiazine commonly used.
IV fluid resuscitation in burns
PARKLAND formula
Lactated ringers : 4ml/kg/%TSA
1/2 run in first 8 hours, other 1/2 run over remaining 16 hours
Depth of 1st degree burn, CP, cap refill
Depth: Epidermis
PE: Erythematous, dry
CP: Painful, tender to touch
Cap refill: intact, blanches w/ pressure
Prognosis: Heals w/in 7 days without scarring
Depth of 2nd degree superficial partial thickness burn, PE, CP, prognosis
Depth: Epidermis + superficial portion of dermis (papillary)
PE: Erythematous, pink, moist, weeping, + BLISTERING
CP: MOST PAINFUL OF ALL BURNS, VERY tender to touch
Cap refill: intact, blanches w/ pressure
Prognosis: Heals w/in 14-21 days without scarring but +/- pigment changes
Depth of second degree burn - deep partial thickness - PE, CP, prognosis
Depth: Epidermis + deep portion of dermis
PE: Red, yellow, pale white - DRY, + BLISTERING
CP: Not usually painful, +/- pain with pressure, decreased 2-point discrimination
Cap refill: Absent capillary refill
Prognosis: 3 weeks - 2 months - scarring common, may need skin graft to prevent contractures
Depth of 3rd degree burn- PE, CP, prognosis
Depth: FULL thickness
PE: Waxy, white, leathery, dry
CP: PAINLESS
Cap refill: ABSENT
Prognosis: Takes MONTHS to heal - does not heal well spontaneously
4th degree burn
Depth: Entire skin into underlying fat, muscle, bone
PE: Black, charred, eschar, dry
CP: PAINLESS
Cap refill: Absent
Prognosis: Does not heal well. Usually needs debridement of tissues & tissue reconstruction
Cyanide poisoning
Cyanide poisoning = Coma & apnea (w/ severe metabolic acidosis)
Dx: H&P, cyanide levels
Tx: “Cyanide kit” = Amyl nitrate for inhalation, IV sodium nitrite
Which kind electrical injury has highest risk for Vfib?
Low voltage AC current
GET EKG!!!
Stage I pressure ulcer
Superficial, NON-blanchable rednesss that does not dissipate after pressure is relieved
Stage II pressure ulcer
Stage II = epidermal damage extending into the dermis - resembles blister or abrasion
Stage III
FULL THICKNESS (just like stage III burn) - may extend to SQ layer
Stage IV
Deepest = extends beyond fascia into muscle, bone, or tendon
Tx pressure ulcer
Stage I-II - wet to dry dressings, local wound care
Stage III-IV - may need surgical debridement
Pyogenic granuloma
MC in kids
Occurs after local trauma
CP: Soft, glistening, friable, red nodule (easily bleeds, ulcerates)
PE: Shave excision w/ cautery of base if pedunculated, non-pedunculated = surgical excision
Pyoderma gangrenosum - what is it? A/w? CP, dx, Tx?
What it is:
Ulcerative skin lesion 2ry to immune dysregulation - NAME IS A MISNOMER - neither gangrenous nor infectious - can see why they originally named it that way tho b/c looks like one huge red infected SEVERE ulcer - actually not pus tho it’s white granular tissue covering the ulcer) - it is nasty like name sounds but not infected - like a huge ulcerated version of a pyogenic granuloma - granuloma sounds like it’s in grandmas but actually in adults
A/w:
IBD, RA, spondyloarthropathies
CP:
Inflammatory erythematous blue-red papules or pustules - PAINFUL necrotic ULCER with irregular purple/violet undermined borders & a purulent base
Dx: Clinical. If need bx, shows neutrophilic infiltration (usu not needed/done)
Tx: Topical corticosteroids or tacrolimus, local wound care
