Dermatology Flashcards
what is the MC cause of Cellulitis?
S. aureus & Group A beta hemolytic strep (GABHS/S. pyogenes)
what’s the s/s of cellulitis?
Local: macular erythema (flat margins, not sharply demarcated), swelling, warmth, and tenderness
what is erysipelas caused by?
group A strep (GABHS)
what’s the s/s of erysipelas vs cellulitis?
well demarcated margins and erythematous
MC involves the face
what’s the tx of erysipelas?
IV PCN, Vanco (if PCN allergy or MRSA suspected)
what is lymphangitis? what are complications of it?
spread of the infection via the lymphatic vessels. Seen as streaking from the infected area following the lymph vessels
complications = bacteremia
where does erysipelas MC occur on the body?
the face
what’s the tx of cellulitis NOT caused by MRSA?
Cephalexin; Dicloxacillin
Clinda or Erythromycin if PCN allergic
what are tx of cellulitis caused by MRSA?
IV Vanco PLUS Zosyn
PO options are: Bactrim (2nd best PO med for MRSA, but doesn’t cover strep well), Clindamycin, Doxy
what bacteria is from a cat bite and what’s the tx?
Cat bite = Pasteurella multocida
Tx: Augmentin (Amox/clavulanate)
-doxy if PCN allergic
what bacteria is from a dog bite and what’s the tx?
Capnocytophaga = bacteria from dog bite
Tx: Augmentin
-2nd line is Clinda + Cipro or Bactrim
what’s the tx for a human bite?
Augmentin
-2nd line is Clinda + Moxi or Bactrim
what’s the tx for a puncture wound?
Cipro (covers pseudomonas)
what is a furuncle (boil)?
deep infection of hair follicle (vs folliculitis is superficial)
what’s the s/s of furuncle
fluctuant abscess w/ central plug (may have surrounding cellulitis)
what’s the tx for furuncle?
I&D, heat compress, PO abx if a/w cellulitis
what’s folliculitis?
superficial hair follicle infection MC from staph aureus
what’s the s/s of folliculitis?
singular or clusters of small papule or pustules w/ surrounding erythema
what’s the tx for folliculitis?
topical mupirocin, clindamycin, erythromycin
PO abx for refractory/severe cases -> Cephalexin, dicloxacllin
what’s a carbuncle?
interlocking furuncles/abscess with multiple openings*** + cellulitis
larger, more painful than furuncle
what’s the tx for carbuncle?
same as furuncle - I&D, heat compress, PO abx if a/w cellulitis
what’s the MC type of skin cancer in the US?
Basal Cell Carcinoma
what are causes of Basal Cell Carcinoma?
sun exposure = main RF
what’s patho of Basal Cell Carcinoma?
slow growing: locally invasive but VERY LOW INCIDENCE OF METS
what are the 3 types of BCC?
Nodular (MC), Superficial, Morpheaform
what’s the MC type of BCC?
Nodular
what’s the s/s of Nodular BCC?
**waxy/pearly, dome shaped, smooth, raised, rolled borders, **telangiectatic, ***central ulceration
***slowly enlarging, doesn’t heal, bleeds easily
MC on face/nose/trunk
how do you dx BCC?
punch or shave bx
what’s the GOLD STANDARD tx for BCC?
Mohs
what’s the MC type of melanoma and 2nd MC type?
superficial spreading = MC type
Nodular = 2nd MC type (most malignant subtype d/t dominant vertical growth phase)
what’s the most malignant subtype of melanoma?
nodular d/t vertical growth
what’s the s/s of superficial spreading melanoma?
lesions may be tan, brown, blue, or black
what’s the s/s of nodular melanoma?
Blueish-black, less variable in color/shape than other subtypes
what’s the Mc type of melanoma found in dark-skinned pts?
Acral lentiginous
what’s the s/s of Acral lentiginous melanoma?
Occur on palmar surfaces of hands, plantar surfaces of feet, and underneath nails
what’s the MOST IMPT prognostic factor for METS from melanoma?
thickness
what’s the tx for melanoma if <1mm in thickness?
wide excision w/ a 1cm wide margin
what’s the tx for melanoma if >1mm in thickness?
wide excision w/ a 2cm wide margin
when do you do LN bx for melanoma?
if LN palpable on exam
what’s precursor of SCC of skin?
actinic keratosis
what’s the s/s of SCC of skin?
red, elevated papule, plaques or nodules with adherent white scaly or crusted, bloody margins
hyperkeratosis, ulceration or hyper pigmentation
non-healing that may bleed w/out trauma
how do you dx SCC of skin? tx?
Bx = dx
Tx = wide local surgical excision
what skin does 1st degree burn involve?
only the epidermis
what’s the s/s of 1st degree burn?
red, dry, mod painful, blanches with direct pressure (refill intact)
what’s the tx of 1st degree burn?
heals w/in 7 days, so no tx
no scarring
what skin does 2nd degree superficial partial thickness burn involve?
epidermis to superficial portion of dermis (papillary)
what’s the s/s of 2nd degree superficial partial thickness burn?
red, moist, weeping
***BLISTERING
MOST PAINFUL OF ALL BURNS, VERY TENDER TO TOUCH
blanches on direct press (refill intact)
what’s the MOST PAINFUL of all burns?
2nd degree superficial partial thickness burn
what skin does 2nd degree deep partial thickness burn involve?
epidermis into deep portion of dermis (reticular)
what’s the s/s of 2nd degree deep partial thickness burn?
red, yellow, pale, **white waxy color, **dry
***BLISTERING, but NOT PAINFUL (b/c of destruction of nerves)
***ABSENT CAPILLARY REFILL
what’s the difference b/w the s/s of 2nd degree burns?
2nd degree superficial partial thickness burn
-BLISTERING AND EXTREMELY PAINFUL AND HAS CAPILLARY REFILL (blanches on direct pressure
2nd degree deep partial thickness burn
- BLISTERING, BUT NOT PAINFUL
- ABSENT CAPILLARY REFILL
what’s the tx for 2nd degree deep partial thickness burn?
heals in 3 weeks-2 months
SCARRING COMMON
what’s the tx for 2nd degree superficial partial thickness burn?
heals in 14-21 days
NO SCARRING
what’s a full thickness burn?
third degree -> destroys all layers of the skin
what’s the initial tx for severely burned pts after removal of source of burn and ABCs?
fluid resuscitation with LR’s
what’s the rule of 9’s for burns in adults?
total head = 9%
total of each arm = 9%
total of each leg = 18%
total of chest (front & back) = 18%
total of abdomen/lower back (front & back) = 18%
***whole trunk is 36%
what burns do NOT require dressing for tx?
superficial burns
what’s the empiric tx of cellulitis?
ABX THAT ARE EFFECTIVE AGAINST MRSA
Clinda, Bactrim, Tetracyclines (Doxy or Mino)
what is serous discharge?
Clean, watery (may have slightly brownish hue)
Result of protein and other fluids
Normal
too much = bad bacteria
what is purulent discharge?
Thick, yellow, green, tan or brown
Not normal
Contains pus, WBCs, dead bacteria and various inflammatory cells (signs of infection)
what’s serosanguinous discharge?
Pale, red, watery
Mixture of serous and sanguineous
-Features added plasma
what’s sanguineous discharge?
Bright red, indicative of active bleeding
Most common in deep partial thickness and full thickness wounds
During inflammation stage of wound, a little indicates proper circulation
what is Type 1 cutaneous drug reaction?
IgE mediated: urticarial and angioedema (immediate)
Urticarial = 2nd MC type
what’s the tx of Type 1 cutaneous drug rxn (urticaria/angioedema)?
systemic corticosteroids, antihistamines?
what’s Type 2 cutaneous drug rxn?
Cytotoxic, Ab-mediated
what’s Type 3 cutaneous drug rxn?
Immune antibody-antigen complex
-Drug mediated vasculitis and serum sickness
what’s Type 4 cutaneous drug rxn?
Delayed (cell mediated)
-Morbiliform reaction (i.e. Erythema multiforme)
what is erythema multiforme?
acute self-limited type 4 hypersensitivity rxn
rash evolves over 3-5 days and persists about 2 weeks
what is erythema multiforme a/w?
herpes simplex virus (MC)***
***Meds: sulfa drugs, beta-lactam, phenytoin, phenobarbital
what are the s/s of erythema multiforme?
***TARGET lesions -> dull “dusty-violet” red, purpuric macules/vesicles or bullae in the center
what’s the tx of erythema multiforme?
d/c offending drug, PO antihistamines, STEROIDS (systemic if severe)
what’s a exanthematous/morbiliform rash?
MC skin eruption
“bright-red” macule & papule that coalesce to form plaques
PERSISTENT LESIONS (vs urticaria are NOT)
caused by abx, NSAIDs, allopurinol, thiazides
rash begins 2-14 days after medication initiation
what drugs cause SJS and TEN?
sulfa and anticonvulsants MC
what is the difference b/w SJS and TEN?
SJS = sloughing <10% body surface area
TEN = sloughing >30% (may develop skin necrosis)
what’s the s/s of SJS and TEN?
fever & URI sx’s -> WIDESPREAD BLISTERS on trunk/face, erythematous/pruritic macule >/= 1 mucous membrane and involves EPIDERMAL DETACHMENT (NIKOLSKY SIGN)
what’s the tx of SJS and TEN?
Treat like severe burns
-burn unit admission, pain control, stop offending agent, fluid replacement, wound care
what’s Dress Syndrome? s/s?
Drug induced hypersensitivity syndrome
S/S = fever, severe exanthematous rash (exfoliative), generalized LAD, hematologic abnormalities
Organ damage = carditis, hepatitis, nephritis
NO mucosal lesions (therefore different from SJS and TENs)
what is urticaria & angioedema? Common med cause?
Type 1 hypersensitivity rxn (IgE mediated)
Commonly caused by CPNs (e.g. Cefotetan and PCNs)
what are the s/s of urticaria?
pruritic, circumscribed, raised erythematous wheals or plaques, with central pallor
transient, blanching
occurs w/in min-hrs after drug administration
what’s the treatment of choice for urticaria and angioedema?
PO antihistamines
