Derm Lecture 1 Flashcards
what are the 3 most common skin and soft tissue infections?
cellulitis, erysipelas, abscess
how do cellulitis, erysipelas, and abscess develop? seen in who?
as a result of bacterial entry via breach of skin barrier
can see a lot with IV drug users or surgery post-op infections
risk factors of cellulitis, erysipelas, and abscesses
skin barrier disruption - trauma, pressure ulcer (ex. nursing home pts)
pre-existing skin conditions - eczema, impetigo, tinea
skin inflammation - radiation therapy
obesity - skin folds rub together
immunosuppression
close contact w/infected people
what layers of the skin does erysipelas affect?
upper dermis and superficial lymphatics
epidemiology of erysipelas
young children and older adults
pathogen of erysipelas
beta-hemolytic streptococci
clinical manifestations of erysipelas
erythema, edema, warmth, tender
ALWAYS UNILATERAL and non purulent
acute onset of sx’s
CLEAR DEMARCATION - butterfly involvement of face
systemic manifestations - fever, chills
what 2 skin infections are usually unilateral?
cellulitis and erysipelas
what skin disorder has clear demarcated borders and which one doesn’t?
clear border = erysipelas
non-demarcated border = cellulitis
erysipelas location
lower extremities M/C, but can be seen anywhere
FACE w/ butterfly shape
erysipelas diagnosis
Based on clinical manifestations and pt hx
Raised above level of surrounding skin with clear demarcations b/w involved and uninvolved skin (vs. cellulitis)
LRINEC SCORE – distinguish NF from other soft tissue infections
what is the LRINEC score and when do you use it? score?
lab risk indicator for NF
-used to distinguish NF from other soft tissue infections
use when pt has:
- concerning hx & exam
- pain out of proportion to the exam
- rapidly progressing cellulitis
score >6 then rule IN NF
what layers of the skin does cellulitis effect?
deeper dermis and subcutaneous fat
cellulitis epidemiology
middle aged and older adults
cellulitis pathogens
beta-hemolytic strep and staph aureus including MRSA
cellulitis clinical manifestations
- Erythema (redness), edema, warmth, tender
- Always UNILATERAL & may present with or w/out purulence
- Indolent course
- More localized sx develop over days
- Less distinct borders
cellulitis location
lower extremities most common site of involvement, but can be seen anywhere
cellulitis diagnosis
Based on clinical manifestations and pt hx
Not clear borders & indolent onset (vs. erysipelas)
LRINEC SCORE – distinguish NF from other soft tissue infections
differential diagnoses of cellulitis
Gout (distinguish w/X-rays or joint aspiration)
DVT (red, warm & swollen bump on leg)
Venous stasis dermatitis
what layers of the skin does an abscess effect?
upper and deeper dermis
abscess pathogens
staph aureus
abscess clinical manifestations
- Erythema (redness), edema, warmth, tender
- Collection of pus w/in dermis or SQ space
- Painful, fluctuant, erythematous nodule with or w/out cellulitis
- Surrounding induration (hardness around infection)
- Regional adenopathy (e.g. abscess in thigh -> groin adenopathy)
-Rare fever, chills, systemic
toxicity
abscess locations
neck, face, axillae, buttocks
abscess diagnosis
Based on clinical manifestations and pt hx
Painful, fluctuant, erythematous nodule
LRINEC SCORE – distinguish NF from other soft tissue infections
what is a furuncle? carbuncle?
furuncle - abscess around follicle
carbuncle - abscess around multiple hair follicles
MEANS ABSCES CAN DEVELOP VIA INFECTION OF HAIR FOLLICLE
what is impetigo?
contagious superficial bacterial infection w/ principle pathogen being staph aureus
who is impetigo most frequently found in?
children 2-5 y/o
can be seen in adults
classification of impetigo
primary impetigo (direct bacterial invasion of normal skin)
secondary impetigo (infection at sites of skin trauma)
epidemiology of impetigo
- Most common bacterial infection in children
- 3rd most common skin condition in children
- More prevalent in summer and fall
- More common in southeast US than northern states
where does impetigo most commonly occur on the body?
the face
types of impetigo (HINT: 3)
non-bullous impetigo
bullous impetigo
ecthyma
non-bullous impetigo clinical manifestations
most common form of impetigo
- papules progress to vesicles surrounded by erythema
- pustules that rapidly enlarge breakdown and form thick adherent GOLDEN CRUSTS
what is the most common form of impetigo?
non-bullous impetigo
will have GOLDEN CRUSTS
bullous impetigo pathogens
staph aureus strain that produces a toxin that causes cleavage in the superficial skin layer
bullous impetigo clinical manifestations
vesicles enlarge to form flaccid bullae with clear fluid
- becomes darker and ruptures leaving thin BROWN CRUSTS (progresses over a week)
- fewer lesions (vs. non-bullous impetigo)
-trunk more affected
what area of the body does bullous impetigo affect more vs non-bullous?
trunk is affected more in bullous impetigo
ecthyma clinical manifestations
ulcerative form of impetigo
-lesions extend through the epidermis to deep dermis
<b>-“punched-out” ulcers covered w/yellow crusts</b>
impetigo diagnosis
- Clinical picture & hx
- Honey colored crusts (non-bullous)
- Brown crusts (bullous)
- Punched out ulcers w/yellow crusts (ecthyma)
- Can gram stain & culture
limited non-bullous and bullous impetigo topical therapy tx
- Mupirocin (Bactroban) TID
2. Retapamulin (Altabax) BID
extensive impetigo and echythma oral therapy and alternative for PCN and ceph hypersensitivity
dicloxacillin or cephalexin
alternative for PCN and ceph hypersensitivity:
-erythromycin OR clarithromycin
impetigo tx if MRSA suspected or confirmed
- Clindamycin OR
- Trimethoprim-sulfamethoxazole OR
- Doxycycline
what is urticaria?
- hives, welts, wheals
- common disorder
- very pruritic, erythematous plaque
is there always a trigger for urticaria?
no, may have no identifiable trigger
what can accompany urticaria?
angioedema
- often presenting as very swollen lips
- can also affect extremities and genitalia
urticaria classification
acute - less than 6 weeks
chronic - recurrent, with s/sx’s recurring most days of the week for more than 6 weeks
urticaria clinical manifestations
Circumscribed, raised, erythematous plaques with central pallor (central clearing)
Intensely itchy - Most severe at night
Any area of body may be affected
Lesions are transient - Appearing, enlarging, and then disappearing within 24 hours
urticaria pathophysiology
Mediated by cutaneous mast cells in the superficial dermis (just in skin)
Mast cells release multiple mediators including:
- Histamine (causes itching)
- Vasodilatory mediators (causes swelling)
urticaria diagnosis
- Clinical exam and history
- Signs and symptoms of allergic reaction
- Any underlying disorder
- No specific lab studies however if allergy is suspected then allergist can test for allergen specific IgE antibodies
what is the focus for tx of urticaria?
focus on short term relief or pruritis and angioedema
2/3 spontaneously resolve and are self-limited
urticaria tx
H1 antihistamines
- Diphenhydramine
- Chlorpheniramine
- Hydroxyzine
- Cetirizine
- Loratidine
- Fexofenadine
H2 antihistamines
- Ranitidine
- Nizatidine
- Famotidine
- Cimetidine
Glucocorticoids
- Prednisone
- used for severe cases or if they have angioedema (will not help itchiness, only antihistamine will)
- may be used w/pts w/sx’s longer than 2-3 days
urticaria H1 antihistamines for tx
- Diphenhydramine
- Chlorpheniramine
- Hydroxyzine
- Cetirizine
- Loratidine
- Fexofenadine
urticaria H2 antihistamines for tx
- Ranitidine
- Nizatidine
- Famotidine
- Cimetidine
when do you use glucorticoids (prednisone) for urticaria tx?
- used for severe cases or if they have angioedema (will not help itchiness, only antihistamine will)
- may be used w/pts w/sx’s longer than 2-3 days
what is a lipoma? what does it consist of?
most common benign soft tissue neoplasm
consists of mature fat cells enclosed by a thin fibrous capsule
lipoma epidemiology
- Occur on any part of the body
- Most commonly on the upper extremities and trunk
- Range from 1-10 cm
lipoma pathophysiology
> 50% develop in the SQ tissue
cause is unknown
-solitary lipomas have been associated with gene rearrangement of chromosome 12
lipoma clinical manifestation
superficial, soft, painless, SQ nodule
round, oval, multilobulated
can occur on any part of body, but MOST COMMONLY ON UPPER EXTREMITIES & TRUNK
lipoma diagnosis
history and PE
- won’t be red, tender or hard
- will grow over time and is movable
lipoma tx
stable and asymptomatic - no tx
surgical excision if:
- cosmesis
- pain (pushing on a joint)
- uncertain about dx
what is an epidermal inclusion cyst?
most common cutaneous cysts
skin-colored dermal nodules
visible central punctum (usually around hair follicles)
epidermal inclusion cyst epidemiology
Occur anywhere on the body
- Anywhere there is hair
- More common on face, scalp, neck, and trunk
Twice as common in men
Seen in hereditary conditions
-Gardener syndrome (get a lot of polyps)
epidermal inclusion cyst pathophysiology
- Implantation & proliferation of epithelial elements into the dermis by result of trauma
- Cyst wall consists of normal stratified squamous epithelium
- Lesions may stay stable or get larger
- Spontaneous rupture can occur
- Cheesy material comes out
epidermal inclusion cyst clinical manifestations and dx
- firm skin-colored nodule with central punctum
- asymptomatic
dx: hx and PE
epidermal inclusion cyst tx
asymptomatic - no tx
symptomatic
- excision of cyst
- incision and drainage
- intralesional injections of triamcinolone (steroid)
