Impetigo

Background

Impetigo is an acute, contagious, apparent pyogenic bark infection that occurs best frequently in children, abnormally those who alive in hot boiling climates. Clinically, physicians admit two abstracted forms of impetigo—bullous and nonbullous. Bullous impetigo is acquired about alone by Staphylococcus aureus, admitting nonbullous impetigo is acquired by S aureus,group A Streptococcus (Streptococcus pyogenes), or a aggregate of both.

Pathophysiology

Impetigo best generally develops at a armpit of accessory agony or insult in which the candor of the bark is disrupted. Adroit bacilli access the epidermis. Alternatively, abrading may anon bathe bacilli below the bark surface, causing impetiginization.

The arrangement of advance of the two adroit bacilli differs. S pyogenes is advance from a being who is adulterated or colonized with the bacilli assimilate the bark of addition individual, area it may account impetigo. The animal again colonizes the adenoids and throat. S aureus, in contrast, spreads aboriginal to the nose. It again spreads to the skin, area it may account impetigo.

Epidemiology

Race

Impetigo can affect bodies of all races.

Sex

In adults, impetigo is added accepted in men.

Age

Nonbullous impetigo can affect all ages, but it best frequently affects accouchement age-old 2-5 years.

Bullous impetigo affects all ages, but, historically, it occurs added generally in newborns and earlier infants. Some authors disagree, advertence that developed cases generally go underreported. 

Impetigo Analytic Presentation

History

Patients with impetigo may address a history of accessory trauma, insect bites, scabies, canker simplex, varicella, or eczema at the armpit of infection, and any history of preexisting bark ache should accession the clinician's basis of suspicion.A nummular eczema bane on the knee, impetiginizeA nummular eczema bane on the knee, impetiginized with Staphylococcus aureus.

Lesions accept usually been present for canicule or weeks rather than months. The lesions are usually painless, although patients may address afire and pruritus.

Constitutional affection are usually absent.

Obtain a history of contacts and alive conditions; bottleneck and poor hygiene can be accidental factors to the advance of impetigo.

Clusters in families and outbreaks in institutions are occasionally reported.

One address declared an beginning amid rugby players, which demonstrates an befalling for impetigo to be advance during acquaintance sports.

Physical

Nonbullous impetigo

Lesions aboriginal activate as thin-walled vesicles or pustules on an erythematous base. The lesions promptly rupture, absolution their serum, which dries and forms a ablaze brown, honey-colored crust.

Multiple lesions about action at the aforementioned site, generally coalescing. The afflicted breadth of bark may enlarge as the infection spreads peripherally.

Bark on any allotment of the anatomy can be involved, but the face and extremities are afflicted best commonly.

Pruritus of adulterated areas may aftereffect in excoriations due to scratching.

As the lesions resolve, either spontaneously or afterwards antibacterial treatment, the crusts accoutrements from the afflicted areas and alleviate after scarring.

If the advance of ache is abiding and patients do not seek treatment, as abounding as 90% will advance bounded lymphadenopathy.Following dermabrasion, this accommodating developed nonFollowing dermabrasion, this accommodating developed nonbullous impetigo in the aforementioned breadth as several canker canker lesions. 

Bullous impetigo

Lesions may anatomy on grossly accustomed or ahead traumatized skin.

The vesicles do not breach as calmly or bound as in nonbullous lesions, but they do enlarge into bullae that are usually 1-2 cm in diameter. The bullae initially accommodate a bright chicken aqueous that after turns blurred and aphotic yellow.

Afterwards 1-3 days, the lesions breach and leave a thin, ablaze brown, varnishlike crust.

Central healing after-effects in circinate lesions.

In adverse to nonbullous impetigo, bullous impetigo may absorb the buccal close membranes, but bounded lymphadenopathy is rare.Bullous impetigo on the buttocks. Courtesy of MediBullous impetigo on the buttocks. Courtesy of Medical University of South Carolina, Department of Dermatology. 

Causes

Nonbullous impetigo

S aureus, accumulation A streptococcus (S pyogenes), or both may be the adroit agent(s) in nonbullous impetigo, but advisers disagree about which animal added generally plays the primary role in infection.

Early studies acicular to streptococci, but contempo investigations advance that S aureus is added the primary communicable organism, abnormally in automated nations.

Evidence indicates that the primary animal varies with cartography and climate; streptococcal impetigo is added accepted in developing nations and balmy climates.

Streptococci are the best accepted primary account back both bacilli are present.

Bullous impetigo

S aureus phage accumulation II blazon 71 is the absolute adroit organism. This ache of bacilli produces an exfoliatin adulteration that causes subcorneal epidermal cleavage.

In immunodeficient or immunocompromised patients, the adulteration may advertise hematogenously and advance to ambiguous staphylococcal scalded bark syndrome.

Impetigo Analysis & Management

Medical Care

Medical administration may absorb contemporary analysis abandoned or a aggregate of systemic and contemporary therapies.

Contemporary therapy

First, abolish the adulterated crusts and bits with soap and water. If the infection is balmy and localized, contemporary mupirocin abandoned may be the alone all-important therapy. Studies announce this contemporary antibiotic, although expensive, is as able as articulate erythromycin for alleviative impetigo. Furthermore, the amount aberration amid these two treatments may be account by the added accident of adverse furnishings associated with erythromycin.

Disadvantages of contemporary analysis are that it cannot eradicate bacilli from the respiratory amplitude and applying contemporary medications to all-encompassing lesions is difficult.

No studies announce that added contemporary antibiotics are as able as systemic therapy.

Systemic therapy

Back infection is abstinent to astringent or accompanied by lymphadenopathy, systemic analysis is indicated.

The biologic adopted for impetigo acquired by S pyogenes is penicillin. Substitute clindamycin in patients who are allergic to penicillin.

In cases acquired by S aureus, clindamycin or cephalexin may be used.

Treat erythromycin-resistant S aureus impetigo with a cephalosporin (eg, cephalexin, clindamycin)

Medication Summary

The goals of pharmacotherapy are to eradicate the infection, to abate morbidity, and to anticipate complications.

Antibiotics

Class Summary

Empiric antimicrobial analysis charge be absolute and should awning all acceptable bacilli in the ambience of the analytic setting.

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Penicillin V (Penicillin VK, Veetids)

Interferes with corpuscle bank mucopeptide amalgam during alive multiplication, consistent in antibacterial action adjoin affected microorganisms. Not recommended for staphylococcal impetigo.

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Cephalexin (Keflex)

Recommended for impetigo acquired by S aureus aggressive to erythromycin. First-generation cephalosporin arrests bacterial advance by inhibiting bacterial corpuscle bank synthesis. Antibacterial action adjoin rapidly growing organisms. Primary action adjoin bark flora. Acclimated for bark infections or prophylaxis in accessory procedures.

Amoxicillin clavulanate (Augmentin)

Indicated for bark and bark anatomy infections acquired by beta-lactamase–producing strains of S aureus that are aggressive to erythromycin.

Administration with aliment may abatement GI adverse effects.

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Clindamycin (Cleocin)

Alternative analysis for S aureus aggressive to erythromycin. Lincosamide for analysis of austere bark and bendable tissue staphylococcal infections. Also able adjoin aerobic and anaerobic streptococci (except enterococci). Inhibits bacterial growth, possibly by blocking break of peptidyl tRNA from ribosomes, causing RNA-dependent protein amalgam to arrest.

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Retapamulin (Altabax)

Topical antibacterial accessible as a 1% ointment. Aboriginal of fresh antibacterial chic alleged pleuromutilins. Inhibits protein amalgam by bounden to 50S subunit on ribosome. Adumbrated for impetigo acquired by S aureus or S pyogenes