| What is impetigo? | common superficial bacterial skin infection, common in children 2-5 yrs, older can get affected, contagious, spread easily, most cases are due to S.aureus/GAS
Non-bullous impetigo (most common form, AKA impetigo contagiosum, papules lesions surrounded by redness, progress to form pustules and breakdown to form honey-crust appearance)
Bullous/Blistering impetigo (seen in young children, flaccid bullae w/clear yellow fluid later becomes purulent, if ruptures leaves a thick brown crust, common locations in face, extremities and diaper
Skin diseases secondarily infected (most common in adults, bacteria penetrates through skin scratch/injury, look for pruritic dermatitis, scabies, eczema, herpes, VZV) |
| How is dx of impetigo? | clinical dx (easily seen), bacterio exam (if complicated/resistant), Basic lesions (fragile vesicle/bubble pustule break-up may lead to polycyclic circumferential contours) classic locations in children around the mouth, skin, general condition preserved and no fever |
| What is ecthyma? | Ulcerative lesion extending to dermis (deep impetigo), punched out ulcer covered w/yellow crust surrounded by raised margins, heals slowly and scars (unlike impetigo), S.aureus/GAS/Pseudomonas (If IC)
AKA ecthyma gangrenosum.
It is necrotic covered with thick crust and surrounded by dark halo usually in lower limbs, could be induced by poor hygiene, IC, DM, alcoholism + Strep usually. heals slowly and leaves a scar |
| How is tx of impetigo? and what are its complications? | Disinfection (topical fucidin/mupirocin if localized lesions)
If widespread (oral Abx - especially clindamycin)
Complications (rare, post-strep glomerulonephritis, RF, control of proteinuria 3 weeks after infectious episode) |
| What is folliculitis? | Superficial bacterial infection of hair follicles (never seen in places where no hair), small raised red occasionally pruritic pustules <5mm diameter, may be STD, usually due to S.aureus, pseudomonas (swimming pools), candidiasis (marked erythema), herpetic...
Pustule is fluid filled lesion w/purulent fluid centered by a hair w/perifollicular erythema, variable in number lesions on hairy regions
Clinical forms (stye [eyelash], sycosis [beard- shaving induces chronicity and extension]) |
| How is tx of folliculitis? | Cleaning w/antibacterial soap, superficial ones rupture and drain spontaneously, maybe oral/topical anti-staph Abx (mupirocin/retapamulin/clindamycin topical), deep lesions are abscesses and should be drained |
| What is furuncle/Boil? | Acute, round, tender, circumscribed perifollicular abscess generally ends in central suppuration, deep necrotic folliculitis, S.aureus [maybe recurrent if resistant, painful papule/nodule centered by pustule and central necrosis]
differential (fungal [candida, dermatophytes], pseudofolliculitis [no pathogen, body rxn, Crohn's disease/eosinophilic folliculitis], Hidradenitis suppurativa (Verneuil's disease): chronicinflammation of the pilosebaceous follicles and sweat glands in areas rich in apocrine glands (axillary, sub- mammary and anoperineal folds), Epidermal inflammatory cyst or superinfected cyst: Preexisting cyst (face) |
| What are complications of furuncle? | Anthrax (conglomerate several boils), furunculosis (chronic boils triggering factors DM/IC), primary abscess, lymphangitis, systemic complications (very rare bacteremia, sepsis), malignant staph of face (emergency, rare, pt manipulates his furuncle of the face usually near labia/nose, causes general staph infection, fever, edema, palpable venuos cord, lead to septic thrombophlebitis, and more severe thrombophlebitis of cavernous sinus [deadly] |
| What is carbuncle? | Coalescence of several inflamed follicules into a single inflammatory mass w/purulent drainage from multiple follicules
Subtype of abscess, usually by staph, pt tx by Abx oral, if solitary small furuncle can compress it to promote drainage, larger ones manage as an abscess |
| How is tx of folliculitis and boils? | General hygiene antiseptic use, for boils give systemic oral Abx active on S.aureus, if comorbidities give penicillin M, macrolides in case of allergy/contraindications, duration for 10 days
Furunculosis we should perform disinfection of portages armpits ,perineum, nasal vestibule...antiseptic toilet and usage of topical antibiotics (fucidin) |
| What is Whitlow (Panaris)? | • Infection of the ungual fold
• Elemental lesion: periungual erythematous and edematous fold, painful
• Treatment: local antiseptics; oral antistaphylococcal antibiotic in case of resistance and/or collection and / or complication; incision and drainage in case of purulent collection |
| What is an abscess? | Collection of pus w/in dermis and deeper skin tissues, painful tender fluctuant and erythematous nodules, surmounted by a pustule and a rim of erythematous edema, absent fever, lymphangitis, satellite adenopathies, good general conditions, spontaneous drainage may occur (like a fistula outside) |
| How is abscess tx? | Abscess incision and drainage recommended to clear pus and debris and probe the entire cavity following incision and drainage.
Abx recommended for abscesses w/severe or extensive diseases (multiple sites, rapid progress to cellulitis, S&S of systemic illness, ass comorbidities and IS, extremes of age, abscess difficult to drain, associated septic phlebitis, and lack of response to I&D alone |
| What is lymphangitis? | Due to S.aureus/GAS, linear inflammatory erythema between site of inflammation and first regional lymph node, palpable lymph node, maybe febrile.
Tx systemic Abx |
| What is superficial septic thrombophlebitis? | • Superficial septic venous thrombosis
• Linked to thrombogenic activity of S. aureus, risk of deep spread and septic emboli
• Clinical presentation: Common form: Venous
Inflammatory cord at the point of infusion, indurated on palpation, fever
• Treatment: Removal of catheter / gateway to an
infection. Antiseptics; systemic antibiotic therapy if resistance / complication; rare form: malignant staphylococcal disease of the face |
| What is cellulitis? | • Cellulitis is a very common infection occurring in up to
3% of people per year
• Most do not require hospitalization
• Results from an infection of the dermis that often
begins with a portal of entry that is usually a wound,
maceration between toes (strepto component), or
fungal infection (e.g., tinea pedis)
• Presents as a spreading erythematous, non-fluctuant
tender plaque
• More commonly found on the lower leg
• Streaks of lymphangitis may spread from the area to
lymph nodes |
| What are risk factors for cellulitis? | Local trauma (bug bites, laceration, abrasion, puncture wound) – Spread of a preceding or concurrent skin lesion
(furuncle, ulcer) Secondary cellulitis from blood-borne
infection or from direct spread of subjacent infections (e.g.
osteomyelitis) is rare
• Following a preexisting skin infection due to compromise of skin barrier (intrerdigital strep, tinea pedis)
• Inflammation (local dermatitis, radiation therapy)
• Edema and impaired lymphatics in the affected area |
| What are etiologies of cellulitis? | • 80% of cases are caused by gram positive organisms
• Group A streptococcus is most common; other strep less so
• Staphylococcus aureus is less common but occurs with open wound or penetrating trauma as with needle injection with drug abuse
• Think of other organisms if there have been unusual
exposures or conditions: Pasteurella multocida (animal
bites)
• Eikenella corrodens (human bites)
• MRSA (with concurrent MRSA elsewhere/illicit drug
use/purulent drainage) |
| What is tx of cellulitis? | • It is important to recognize and treat cellulitis early as untreated cellulitismay lead to sepsis and death
• The following guidelines are for empiric antibiotic therapy: For outpatientswith nonpurulent cellulitis: empirically treat for β-hemolytic streptococci (group A streptococcus) as cephalexin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, or clindamycin
• For outpatients with purulent cellulitis (purulent drainage or exudate in the absence of a drainable abscess)/injection drug use/other penetrating trauma/MRSA presence elsewhere: empirically choose treatment to cover community-associated MRSA as well as strep, as clindamycin; work with dermatology and infectious disease specialists
• For unusual exposures: cover for additional bacterial species based on such exposure; work with dermatology and infectious disease specialists |
| How is post tx of cellulitis? | • Monitor patients closely and revise therapy if there is a poor response to initial treatment; usually a 5 day course of antibiotics is sufficient
• Treat underlying derm disorder/condition, as venous eczema
• Elevation of the involved area
• Treat tinea pedis, toe maceration (strep) if present
• Consideration of concurrent oral steroid treatment to decrease post- inflammatory lymphatic damage; more studies needed
• For hospitalized patients: empiric therapy for MRSA should be considered
• Cultures from abscesses and other purulent skin and soft tissue infections (SSTIs) are recommended in patients to be treated with antibiotic therapy but if case has a typical presentation, they need not be performed |
| What are MRSA risk factors? | • Healthcare-associated MRSA (HA-MRSA) and community-associated MRSA (CA- MRSA) risk factors include:
. Antibiotic use
•Prolonged hospitalization
•Surgical site infection
•Intensive care
•Hemodialysis
•MRSA colonization
• Proximity to others with MRSA colonization or infection
• Skin trauma
• Cosmetic body shaving
• Group facilities
• Sharing equipment that is not cleaned or laundered between users/body contact
as in sports |
| What is erysipelas? | • Erysipelas is a superficial cellulitis with marked dermal lymphatic involvement (causing the skin to be edematous or raised) Main pathogen is group A streptococcus
• Also caused by Staph aureus, Haemophilus, and others
• Usually affects the lower extremities and face
• Presents with pain, bright erythema, and plaque-like edema with a sharply defined margin to normal tissue
• Plaques may develop overlying blisters (bullae)
• May be associated with a high white count (>20,000/mcL)
• May be preceded by chills, fever, headache, vomiting, and joint pain |
| What is tx of erysipelas? | • Immediate empiric antibiotic therapy should be
started (cover most common pathogen - Streptococcus) Such as penicillin V, amoxicillin, clindamycin, macrolide, and others
• Monitor patients closely and watch the therapy if
there is a poor response to initial treatment
• Elevation of the involved area
• Treat tinea pedis, erythrasma, or intertrigo |
