Common Infections Of The Skin Flashcards
What are the most common types of bacteria for skin infections
Gram (+)
- especially staph aureus
Impetigo
Caused by staph and GAS
**Most common bacterial skin infection in pediatrics
Shows honey-colored crusted plaques/papules/vesicles/Bullae
Also called “impetiginized” skin
- “ecthyma” is deeper more punched out impetigo (looks kinda like gun shot wounds)
- specific treatment for ecthyma = cephalexin
Complications = rare and usually benign (only 5% leads to any of the below)
- post streptococcal Glomerulonephritis
- staph scaled skin syndrome
Treatment = mupirocin or retapamulin ointment
Folliculitis
Superficial or deep infections around hair follicles
- **staph aureus is most common pathogen
- **“hot tub” folliculitis is from pseudomonas however
Risks = occlusion, sweating/increased humidity, increased steroid use, poor shaving/hygiene
Forms follicular based erythematous papules/pustules
Treatment = antibacterial washes, mupirocin
- oral doxycycline as last line or complications
Pseudofolliculitis barbae
Folliculitis caused by poor shaving practices and results in irritation
- looks kinda like folliculitis but is caused by curving of the hair follicle which causes the tip of the hair follicle to embed back into the the skin and cause inflammatory response to the keratin in the hair.
Treatment = change shaving practices and a topical clindamycin aftershave
Gram (-) folliculitis
Caused by patients who are using long term steroids or oral antibiotics
Treatment = isotretinoin (accutane)
Furuncle/carbuncle
Furuncle = folliculitis that looks like a boil
- surrounding tissue is also acted on
Carbuncle = groups of furuncle and presents with systemic system
Treatment = oral antibiotics and topical antibiotics as needed
Abscesses
Can be anywhere on the skin and is localized collection of pus that causes inflamed skin
Treatment = incision and drain as needed, culture, and then antibiotics and pack the abscess
Cellulitis
Most commonly caused by GAS and Staph aureus
Immunocompentent = must have had a break in the skin Immunocompromised = could also be blood borne
Produces erythema, warmth, tenderness and irritation
- bilateral cellulitis = venous stasis dermatitis MUST be #1 on your differential*
- normal cellulitis is more commonly unilateral
Erysipelas
St. Anthonys fire
Superficial variant of cellulitis that usually is on the face
- is caused by GAS
- more common in females vs males and bimodal distribution with. Young and elderly
Incubation of 2-5 days and then abrupt onset of fever, chills and malaise.
- also reports burning sensations and lymphadenopathy
Treatment = doxycycline usually
Perianal strep
Caused by GAS
- more common in males <4 yrs
Almost always preceded strep throat or colonization of the tonsils (but not necessarily)
Shows pain, pruritis, blood/fecal incontinence in stool
- shows erythematous nummular patch around the anus
- **no systemic symptoms
Need to rule out candida, pinworms and IBD
Tx= topical antibiotics (mupirocin) and oral cephalosporin
Pitted keratolysis
Caused by corynebacterium, actinomycosis and kytococcus sedentarius organisms
- ***all of these secrete proteases specific to the stratum corneum and causes sponge like holes in the stratum corneum
- almost always on the feet and smells horrific also
Risk factors = humidity, hyperhydrosis (over sweating) and occlusion
Treatment = topical erythromycin/Clindamycin
- also give aluminum chloride or Botox if the patient has super sweaty feet
Verrucae vulgaris (warts)
Caused by HPV (most common are 6/7 subtypes)
Hyperkeratosis papules/plaques that grow overtime
- also can cause thrombotic capillaries with in the wart (this confirms its a wart and looks like black spots)
- also shows interruption of dermatoglyphs (lines in the skin get disrupted)
Treatment = very difficult!
- cryotherapy is #1
- Topical such as cantharidin/salicylate Acid and 5-FU combo therapy/cimetidine
- immunotherapy
- laser therapy
- injection of candida species
- HPV vaccine (prophylaxis only, doesnt treat active warts)
Molluscum contagiosum
Most common Pox virus infection
- very common in children
- if patient is immunocompromised = giant lesions
Shows pearly red papules with central dell on them
- Is sexually trasmittable but also contact as well
Patients with eczema are also at very high risk since their stratum corneum is naturally deficient
Treatment = benign and self-limiting, however can also give topical irritants (cantharidin)
Hand foot mouth disease
Coxsackie A16 or enterovirus 71 causes it
- coxsackie A6 = more severe bullous form
Shows gray/white vesicular lesions on the palmoplantar skin
- also shows systemic symptoms such as fever, malaise, anorexia, dehydration
Treatment = supportive only
Erythema infectiousum
“Fifth disease/ slapped cheek disease”
Parvovirus B19 causes this and is spread via respiratory droplets
- almost exclusive to 4-10 yrs old
Prodromal symptoms of fever, headaches and malaise
- once rash starts = not infectious any more
Treatment = supportive and goes away
Roseola infantum
“Sixth disease”
Caused by HHV6/HHV7 viruses
= common in 5 months-4yrs
Causes high grade fever in 3-5 days and can induce seizures if not supportively treated well
Treatment = supportive and goes away
Pityriasis rosea
Papulosquamous eruption
- most commonly seen in 10-35 yr old patients
Produces herald patches with smaller versions around in a Christmas tree distribution
Treatment = topical clindamycin if needed. Lasts 6-8 weeks usually and Will go away
Herpes zoster
Caused by VZV or HHV-3 infections
- hits older patients more than younger but everyone can get it
Prodromal = pruritus, tingling, tenderness, hyperesthesia, pain
- often causes pain first before skin eruptions often
- produces a grouped dermatome pattern that is sometimes crusted
Treatments = antivirals (especially IV acyclovir if patient is immunocompromised)
- NSAIDs
- topical steroids
- Gabapentin for neuralgia
- rash usually goes away overtime
Hutchinsons sign
VZV on nose specifically and affects the nasocillary branch of the ophthalmic nerve
must worry about ocular involvement such as conjunctivitis, episcleritis, keratitis, uveitis, optic neuritis
Should treat this aggressively with antivirals to prevent eye damage and also contact ophthalmologist
Ramsay hunt syndrome
VZV of the geniculate ganglion of the facial nerve
- shows VZV in the external auditory canal, tympanic membrane and hard palate
Symtpoms:
- ear pain
- facial nerve paralysis
- loss of taste in anterior 2/3rds of tongue
- dry mouth and eyes
Condyloma acuminata
“Genital warts”
HPV types 6/11/16/18 are most common
- 16/18 are especially high risk for cancer involvement
Treatment = destruction via liquid nitrogen and/or cantharidin
- also topical imiquimod/podophyllin
- HPV vaccine for safety
Herpes
HSV-1 (orolabial) HSV-2 (genital)
- either can cause both though
Usually remains dormant until a Trigger activation occurs
- emotional stress
- UV light
- fever
- local tissue damage
- immunosupression
Looks like punched out lesions and need a sank smear to look for giant cell nuclei which are indicative of dormant herpes
Treatment = antivirals
What is the most common cause of tinea corporis?
Trichophyton rubrum
Tinea incognito
Tinea infection that is being treated with topical steroids
- infection becomes less scaly and more pustular/papular
Needs oral/topical antifungal with the steroids if it occurs
Proximal subungual onychomycosis is usually seen in what types of patients?
Immunocompromised especially in aids patients
Onychomycosis treatment
Very challenging
Topicals = Tavaborole/efinaconazole
Systemic = terbinafine
Physical debridement
Home remedies (vicks vapor rub or vinegar baths)
Must treat tinea pedis if present
Tinea versicolor “pityriasis versicolor”
Subtype of tinea that is casued by malassezia furfur fungi
Circular/oval shaped macules/patches with fine scale when active
- most commonly found on trunk, upper extremities and neck
Shows changes in skin color due to increased production of dicarboxilic acid which inhibits melanin production
Treatment = selenium sulfide shampoo and topical antifungals
Pityrosporum folliculitis
is casued by malassezia furfur in the hair follicle
Mysore common in females than males
Shows monomorphic follicular papules near the hearing line or on the trunk near hair:skin contact sites
Treatment = selenium sulfide, topical and systemic antifungals
