Lecture 36 Dermatology infections Flashcards
What bacteria are usually involved in skin infections, what conditions can exacerbate, and complications from it?
most commonly staph and strep
Exacerbating Fx: DM, vascular insufficiency, immunocompromised, IV drug use
Complications: skin breakdown, abscess formation, sepsis, septic emboli, scarring or postinflammatory hyperpigmentation, infections due to resistant bacteria (ex. MRSA) more difficult to treat
What is impetigo (S&S, classes, organism(s))?
S&S: first sign is patch of red itchy skin, pustules develop soon forming crusty honey coloured sores that can spread to cover entire areas of face, most pt are children
characterized by pustules and honey-coloured crusted erosions
contagious
secondary infection of wounds or other skin lesions with the same pathogens is called ‘impetiginization’,, Classes: Non-Bullous - starts with one lesion, limited erythema, lesions burst and form honey coloured crust, pt generally feel well)
Bullous - quick bullae formation, ruptures and oozes yellow fluid, systemic sx may be present
Organism: S. aureus (most of the time) - individual may be carriers (nares, skin folds, perineum)
S. pyogenes
What is non-pharm and pharm tx for impetigo, and when is pharm tx warranted?
is self-limiting (2-3 weeks) but antibiotics provide quicker healing
Non-Pharm: avoid sharing towels and clothes, frequent hand-washing and other laundry, avoid close contact with others, antiseptic washes to cleanse area may be recommended (chlorhexidine)
Pharm: topical antibiotics, SYTEMIC antibiotics are warranted if ⇒ pt has systemic sx (ex. fever), widespread disease, immunocompromised, renal disease, valvular heart disease, no improvement with topical tx
What are antibiotic options for impetigo, both topical and systemic (monitoring as well)?
NOTE* - prior to topical crusts should be removed with warm water or saline compresses or soap and water washes, topical works well if lesions are limited to 2-3 SPOTS
Topical: Mupirocin - against Gram + only, apply BID-TID F5D or until lesions healed
Fusidic Acid - against Gram + only, apply BID-TID F5D or until lesions healed,, Polysporin (ex. polymyxin B, B. bacitracin, gramicidin, neomycin) - inferior to prior two, apply TID for up to 7D or until lesions healed
Systemic: most S. aureus are MSSA ⇒ usually 7 day regimen with amox/clav OR cefadroxil OR cephalexin OR cloxacillin,, if MRSA ⇒ doxycycline OR clindamycin OR TMP/SMX
Monitor/FU: pt no longer considered infectious approx 2 days after start of tx, monitor for development of systemic sx, vesicles, crusts, bullouses, development of hypo/hyperpigmentation
What is folliculitis (organisms, non-pharm, pharm)?
small raised inflamed pruritic pustules <5 mm in diameter
majority by S. aureus but others like Pseudomonas may be as well (exposure to hot tub/swimming), non-infectious versions (pseudo this) are induced by friction and/or occlusion
Non-Pharm: lesions will rupture, warm water or saline compress to drain, wash area with soap and water, cover with sterile dressing, wash items touching lesion daily
Pharm: TOPICAL ANTIBIOTICS - mupirocin, fusidic acid, Polysporin (polymyxin B, B. bacitracin, gramicidin, neomycin)
SYSTEMIC ANTIBIOTICS - oral if ⇒ inadequate response to incision and drainage, multiple lesions, lesions where draining is difficult, comorbidities, immunosuppression, systemic sx of infection
Options: TMP/SMX, doxycycline, minocycline, clindamycin, if MSSA cephalexin or cloxacillin,, possible IV for immunocompromised
What are bacterial abscesses (organisms, non-pharm, pharm)?
collection of pus within dermis and deeper tissue, painful, tender and inflamed nodule, may have overlying pustule surrounded by rim of inflammation and edema
includes: Furuncles - occurs in skin containing hair follicles, extension into dermis and SC (usually MSSA or MRSA), and Carbuncle - in skin containing hair follicles, multiple furuncles coalesce into single purulent mass (usually MSSA or MRSA)
Non-Pharm: lesions will rupture, warm water or saline compress to drain, wash area with soap and water, cover with sterile dressing, wash items touching lesion daily
Pharm: TOPICAL ANTIBIOTICS - mupirocin, fusidic acid, Polysporin (polymyxin B, B. bacitracin, gramicidin, neomycin)
SYSTEMIC ANTIBIOTICS - oral if ⇒ inadequate response to incision and drainage, multiple lesions, lesions where draining is difficult, comorbidities, immunosuppression, systemic sx of infection
Options: TMP/SMX, doxycycline, minocycline, clindamycin, if MSSA cephalexin or cloxacillin
possible IV for immunocompromised
What are some dermatological viral infections?
HPV types 1, 2, 27, 57: thick endophytic sloping sides, central depression, can be painful ⇒ palmar/plantar warts
HPV types 1, 2, 4, 27, 57: fingers, knees, elbows, nailfold, hyperkeratotic, exophytic, dome shaped, punctate black dots ⇒ common warts
HPV types 3, 10, 28, 29: skin colored or pink on white skin, smooth surface, flat topped
mainly dorsal hands, arms, face ⇒ flat warts
What are pharmacological tx for viral skin infections?
cantharidin 0.7%, bleomycin sulphate intralesional injection, imiquimod 5% cream, 5-FU 5% cream, DPCP, topical retinoids, cimetidine
What is cantharidin (strength, how its used, AE)?
used for viral skin infections
Strength: 0.7%, in office tx
Usage: blistering agent produced by beetles used in recalcitrant cases with multiple lesions or in young children, pain and blisters occur up to 48 hours after application, repeated applications at intervals of 1-3 weeks occasionally needed, cure rates as high as 80%
AE: pain, post-inflammatory pigment alteration, toxic if ingested
What is bleomycin sulphate (strength, how its used, AE)?
used for viral skin infections
Strength: 0.1-1 units/mL, intralesional injection
Usage: chemotherapeutic agent that inhibits DNA synthesis in cells and viruses, injecting directly into wart over 1-3 treatments, cure rates 65-85%
AE: local anaesthesia necessary since its painful during and up to 2 days after tx
not to be used in children, pregnancy, immunosuppressed, vascular disease
What is imiquimod (strength, how its used, AE)?
used for viral skin infections
Strength: 5% cream
Usage: topical immunomodulator enhancing cell-mediated immunity, applied overnight 3 x weekly or up to BID
painless non-scarring option
AE: local pain, pruritus, irritation
What is 5-FU (strength, how its used, AE)?
used for viral skin infections
Strength: 5% cream
Usage: blocks RNA and DNA synthesis and damages dividing basal layer cells, applied to hands and feet QD for 4-12W, apply occlusive covering
cure rates 60%
AE: inflammation with occasional erosions and hyper/hypo pigmentation can occur particularly in dark skin, requires SUN PROTECTION
What is DPCP (usage, AE)?
used for viral skin infections
Usage: contact immunotherapy involving topical application of contact allergens to induce sensitization, two weeks later lower conc that are titrated are applied twice weekly F10D
cure rates 65%
AE: erythema, edema, pruritus, burning, pigment changes (particularly dark skin), desquamation
What are topical retinoids for viral skin infections (usage, AE)?
Usage: topical conc 0.025-0.1% disrupts epidermal proliferation and differentiation to reduce wart volume
applied QD-BID for 6-12W,, cure rate 85%
oral have some efficacy
AE: skin irritation and dryness
What is cimetidine for viral skin infections (usage, AE)?
Usage: oral H2RA, proposed to increase cell-mediated immunity by blocking T-suppressor cells on H2Rs
dose of 30-50 mg/kg/day in 4 divided doses for up to 3 months was effective in open-label studies
AE: drug intx
What is onychomycosis (S&S, causes, diagnosis, non-pharm, pharm)?
fungal nail infection that may require prolonged tx,
S&S: may cause discomfort, pain, disfigurement, rarely remits spontaneously, reinfection common, can spread to other nails and skin
Causes: dermatophytes (Epidermophyton, Microsporum, Trichophyton genera), Yeasts (mainly Candida)
Diagnosis: dermatologist through direct microscopy (KOH exam of scrapings), biopsy, culture
Non-Pharm: wear footwear and socks that minimize humidity, don’t share clippers of footwear, keep nails clean and short, prevent trauma
Pharm: most used for 3-6 months, ex. efinaconazole, ciclopirox olamine, propylene glycol/urea/lactic acid, itraconazole, terbinafine
What is efinaconazole for onychomycosis (strength, usage, AE)?
Strength: 10% solution
Usage: apply 1 drop to affected nail QD, preferably QHS , 2 drops on affected toe for 48 weeks
AE: dermatitis, do not use near open flame
What is ciclopirox olamine for onychomycosis (strength, usage, AE)?
Strength: 8% lacquer
Usage: QD preferable QHS to affected area, clean with isopropyl alcohol weekly, file loose nail material and trim nails after cleansing for 48 weeks
AE: erythema, do not use near open flame
What is propylene glycol/urea/lactic acid for onychomycosis (strength, usage, AE)?
Strength: 66.4%/20%/10% solution
Usage: apply to affected area and under free edge QD, cover nail with thin layer, after application allow to dry for few minutes, for 24 weeks
AE: whitening of affected nail, transient irritation, nail may become brittle
What is itraconazole for onychomycosis (strength, usage, AE)?
Strength/Usage: Pulsed - adults 200 mg BID PO once weekly for 2 months for fingernails and 3 months for toenails
Continuous - adults 200 mg QD PO for 6 weeks fingernails and 12 weeks toenails
can be used in children dosed by weight
AE: GI upset, H/A, minor rashes, serious or fatal hepatotoxicity (rare), HF
What is terbinafine for onychomycosis (strength, usage, AE)?
Strength/Usage: adults 250 mg QD PO for 6-12 weeks for fingernails and 12-24 weeks for toenails, can be used in children dosed by weight
AE: GI upset, H/A, minor rashes, sensory loss of smell or taste, hearing disturbances, serious or fatal hepatotoxicity
it inhibits CYP2D6 as well
