Derm I Flashcards
Pt presents w/ purulent lesion on one leg that developed over the past several days, no systemic sxs
Cellulitis
Pt presents w/ a well demarcated erythematous butterfly lesion that developed acutely + fever & chills
Erysipelas
Pasteurella multocida
cat bite
Capnocytiphaga canimorsus
dog bite
Erysipelothrix rhusipathiae
petting zoo –> goat, camel, llama bite
Vibro vulnificus
ocean related
Pseudomonas aeruginosa cellulitis common in
diabetics, IC pts, hospitalizations
Sporothrix schenckii
rose gardener
Where do skin abscess’ collect
within the dermis or SC space
Pt presents with painful, fluctuant, erythematous nodule & regional adenopathy
Skin abscess
For Skin & Soft Tissue infections, which dz has systemic sxs and which do not
systemic - Erysipelas
non-systemic - cellulitis & skin abscess
MC pathogens for Erysipelas
- beta hemolytic strep
- staph aureus
MC pathogens for Cellulitis
- beta hemolytic strep
- staph aureus (including MRSA)
MC pathogens for Skin abscess
-staph aureus (including MRSA)
mostly bacterial but can be viral
furuncle vs carbuncle
-skin abscess of a single hair follicle vs multiple hair follicles
Dx of erysipelas vs cellulitis vs skin abscess
- manifestation & hx
- ultrasound for diff. between cellulitis (cobble stone appearance) vs. skin abscess (fluid filled)
LRINEC Score (use/when/meaningful value)
- used to distinguish Necrotizing Fasciitis from other soft tissue infections
- use when: concerning hx/exam, pain out of proportion to exam, rapidly progressing cellulitis
> 6 rules in NF
Complications of Cellulitis
- NF –> OR debridement
- Bacteremia & Sepsis –> draw blood cultures
- Osteomyelitis –> get X-Rays
- Septic joints –> aspirate, can culture
Differential dx for cellulitis/erysipelas
Gout, DVT, Venous stasis dermatitis
If cellulitis/erysipelas not responding to abx w/in 24-48 h –> consideration?
underlying abscess
most common bacterial infection in children
impetigo
3 y/o pt presents with thick golden crust around mouth –> 1st line management?
non-bullous impetigo
Topical Therapy: Muprocin (Bactroban) TID, Retapamulin (Altabax) BID
Progression of non-bullous impetigo
papules –> vesicles surrounded by erythema –> rapid enlargement & breakdown –> form thick adherent golden crusts
5 y/o presents w/ dark brown crusted lesion on his trunk –> what pathogen is most likely & how does it cause this lesion?
bullous impetigo
S. aureus –> produces a toxin to cleave the superficial layer
Progression of bullous impetigo
vesicles enlarge –> form flaccid bullae w/ clear fluid –> darken and rupture –> thin brown crust
pt presents with punched out lesions covered w/ yellow crusts –> what pathogen is most likely?
Ecthyma
Group A beta-hemolytic Strep pyogenes
Non-bullous impetigo most often caused by:
Staph aureus
less commonly –> beta-hemolytic strep group A
DX of Impetigo
- manifestation + hx
- gram stain + culture
Pt with extensive Impetigo or punched out ulcers –> management?
Oral Therapy
- Dicloxacillin 250 mg QID
- Cephalexin 250 mg QID
Pt presents w/ intensely pruritic, erythematous plaques with central pallor & a swollen upper lip, pt reports increased discomfort @ night for the past 8 weeks –> management?
Chronic urticaria (> 6 weeks)
H1 +/- H2 antihistamine
D/T angioedema and severe sxs –> Prednisone 30 - 60 mg QD (taper over 5 - 7 days)
what % of the population experiences urticaria? age/gender predilection?
20% –> often no trigger
affects all ages/genders
pt develops multiple raised, circumscribed, erythematous plaques that are intensely itchy, and transiently disappear –> what mediated this reaction?
Cutaneous mast cells in the superficial dermis
-release Histamine (pruritus) & vasodilators (Swelling)
If allergen is suspected cause of urticaria, what testing is ordered
serum test for allergen specific IgE aBs
Management of urticaria focused on
-short-term relief of pruritus & angioedema (H1 +/- H2 antihistamine)
H1 antihistamines
diphenhydramine, chlopheniramine, hydroxyzine, certirizine, loratidine, fexodfenadine
H2 antihistamines
rantidine, nizatidine, famotidine, cimetidine
When do we consider glucocorticoids for the management of urticaria?
- sxs > 2 - 3 days
- severe sxs
- angioedema
Most common benign soft-tissue neoplasm
lipoma
pt presents w/ a solitary soft, painless, subQ nodule; round on torso –> what is a possible genetic association?
gene rearrangement of chromosome 12 –> solitary lipoma
> 50% lipomas develop where?
% of the population to develop a lipoma?
in the subQ tissue
majority are on upper extremities or trunk
1% of population
Dx of lipoma
- Hx & PE
- can ultrasound to determine if nodule is solid vs. liquid
Management of Lipoma
- asymptomatic –> no treatment
- cosmetic issues, pain, or uncertain dx –> surgical excision
Most common cutaneous cyst
Epidermal inclusion cyst
pt presents w/ a firm, skin-colored dermal nodule w/ a visible central punctum –> what is the pathophysiology
-implantation & proliferation of epithelial (junk) elements into the dermis d/t trauma –> lesion can stay stable or grow –> spontaneous rupture –> cheesy material
Who is most likely to develop an epidermal inclusion cyst
men (2x more likely)
certain hereditary conditions –> Gardener syndrome
Dx & management of epidermal inclusion cyst
- Hx & PE
- asymptomatic –> no treatment
- can excise cyst or incision & drainage
- intralesional injections w/ Triamcinolone
