Major skin infections with pygenic germs

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  • Skin manifestations in relation to the presence of pyogen germs in the body
  • Normal skin is colonized by a bacterial flora (one million/cm2)

Resident Flora (permanent): includes:

  • Cocci Gram: Staphylococcus epidermis, captis, hominis
  • Gram bacilles: corynebacteria
  • Gram bacteria (-): cocci (Neisseria) and bacillus (Acinetobacter, Proteus…)

Transitional (contaminant) flora: resulting from external contamination or mucous portage. The most common infections are pyogen germs, Golden Staphylococcus and Streptococcus (Aureus and Pyogenes)

  • There are several levels of skin defense against pathogenic bacteria:

Mechanical protection: thanks to the continuity of the corneocytes

Chemical protection: related to skin pH (neighbouring 5.5), sebum (which covers corneocytes strengthening the keratinocytic barrier)

Biological protection: by the constant presence of a protective bacterial flora

Immune activity: highly developed (skin langerhan cells)

  • The alteration of one or more of these defence mechanisms is responsible for the occurrence of the following skin infections



  • Impotigo is a superficial bacterial (epidermite), non-follicular, self-inoculable and non-immune bacterial skin infection
  • Promoted by promiscuity, poor hygiene and skin break-in


  • Age: especially the child (5-6 years), sometimes newborn and infant, sex-ratio – 1

Adult: in the form of impetiginization (on pre-existing dermatosis)

  • Contagiousness: highly contagious, small family or community epidemics
  • Germs: Pathogenic Golden Staphylococcus (70%), Streptococcus –hemolytic (25%), Streptococcus -hemolytic (10%)


Description type: the child's vesiculo-bubble impetigo

  • Elemental injury:

Surface vesiculo-bubble: a few millimetres to 3 cm, under-horned, rapidly cloudy (pustule), flaccid and fragile, rapidly evolving towards the formation of:

Erosion: erythmatous, oozing, superficial, covered with:

Crusts: yellowish, melicical (honey colour), centrifugal extension – peripheral inflammatory areole

It coexists with lesions of different ages (bubble blister, erosion, crusts)

  • Grouping: either isolated or grouped into crusting plates by peripheral extension with tendency to central healing, circumnate appearance
  • Topography: often peri-orificial at first, then diffusion to the face () and then to the rest of the body by manual portage
  • Functional sign: moderate pruritus
  • Associated signs: frequent regional adenopathy, absent general signs (no fever)

Clinical forms:

  • Giant phlyctenular impetigo (bubble impetisor): characteristic form of newborn and infant, in the form of small sporadic epidemics (creches, maternity wards), by manual carrying of health care workers (staphylococcal)

Clinical: Large bubbles (1-2 cm) with peripheral rash

  • Impetigo ecthyma: impetigo digging, touching the epidermis and derm (ulcerative)

Positive factors: venous stasis, poor hygiene, diabetes, alcohol, HIV

Germ: Staphylococcus, Streptococcus- Group A hemolytics, mixed

Clinical: necrotic ulceration covered with black crusts

Seat: lower limbs

  • Impetiginization (adult impetisigo): secondary to pre-existing dermatosis by Staphylococcus or Streptococcus, dermatosis becomes oozing and purulent. Always eliminate pruriginous dermatosis (gale, contact eczema)

Positive diagnosis:

  • Interview: age, epidemic, pre-existing dermatologist
  • Clinical: polymorphic appearance, seat (peri-orificial)
  • Bacteriology: rarely requested, useless in practice
  • Histology: rarely requested

Evolution / Complications:

  • Under treatment: lesions regress within a few days, without leaving a scar (except in ecthyma)
  • Untreated:

Septic complications:

  • Local: abscess, pyodermitis, lymphangitis, more rarely osteomyelitis
  • General: bacteremia, sepsis, pneumonia

Immunological: acute glomerutonephritis due to Group A Streptococcus (proteinuria will be systematically s searched for 3 weeks later)


  • Acute Staphylococcal Epidermolysis: SSSS (Staphylococcal Scalded Skin Syndrome)
  • Staphylococcal Scarlet fever: diffuse rash, predominant in creases and not accompanied by bubbles, evolving towards flaking in 10-20 days

Recurrent: take samples from Staphylococcus (nasal pits) from the patient and the family because there is chronic portage in a healthy person


  • General measures: school eviction for a few days, examine the environment especially in the community, possible treatment of cottages in Staphylococcus if recurrences, hygiene measures (wearing clean underwear, short cut nails), treatment   etiological of an underlying pruriginous dermatosis
  • Local treatment: it is systematic and often sufficient in small forms

Washing: bi-daily, with soap and water

Antiseptics (Chlorhexidine, iodine povidone, potassium permanganate) and/or topical antibiotics (fusidic acid, Mupirocin): in bi- or tri-daily application

Duration: 8 to 10 days

  • General treatment:

Indications: Extensive, Extensive Lesions, Major General Signs

Choose a broad-spectrum antibiotic (acting on Staphylococcus and Streptococcus): Penicillin M (Oxacillin, Cloxacillin: 30-50 mg/kg/d), Amoxicillin – clavulanic acid or cephalosporin 1st generation, Synergistine (Pristinamycin: 30-50 mg/kg/d) or fusidic acid (1-1.5 g/d in adults, 30-50 mg/kg/j in children)

Duration: 10 days

Follicular infections:

Infections of the hair-sebaceous follicle, most often due to Golden Staphylococcus

  • Folliculites:

Surface folliculitis:

  • Clinical: papulo-pustules centered by a hair and soft-based
  • Seat: face (beard, forehead), trunk (back, anterior face of trunk), gluteal area and legs
  • Evolution: acute, by thrusts
  • Treatment: mainly local, 2x/d for 8-10 days, local antiseptics (Hexamidine or iodized derivatives), general hygiene rules

Deep folliculitis:

  • Clinical: red nodule, firm, painful, surmounted by a pustule and centered by a hair
  • Evolution: subaige, without evacuation of pus
  • Treatment: for 8-10 days, local treatment (at 2x/d, antiseptics and topical antibiotic), sometimes general anti-Staphylococcus treatment (Oxacillin)
  • Boils: deep folliculitis, necrotizing (necrosis of the entire pilo-sebaceous apparatus)


  • Isolated boil: begins with a deep folliculitis and then appears a necrotic, yellowish area called the "bubble" that will be eliminated leaving an ulcerated area, cerrioform, healing with permanent scar
  • Anthrax: it is an agglomerate of boils, producing a hyperalgic inflammatory closet, dotted with pustules

General Signs: Fever and Regional Adenopathy

  • Malignant staphylococcia of the face: rare, it complicates the handling of a mid-facial boil

Clinical: deep dermo-hypodermitis of the face – marked general signs

Evolution: towards a severe cavernous sinus thrombophlebitis

  • Recurrent boil (furonculosis): evolves in flares spaced a few weeks to months, observed in young male adults most often

Positive factors: diabetes, seborrhea, hypersudation, poor hygiene, obesity, immune deficiency

The concept of healthy carrying of Staphylococcus is essential (in the patient or the entourage), of which 60% of cases are intermittent carriers

Staphylococcus deposits: nasal pits (50%), intestinal environment (20%, especially infants), perineum and creases (25%: umbilical, armpits, retro-ear, external ear canal)


  • Insulated boil or anthrax:

General anti-Staphylococcus antibiotic therapy: indicated if isolated but voluminous boil, mid-facial boil, anthrax, furonculosis, existence of general signs, terrain (diabetic, immunodepression). The molecules are then Penicillin M, synergistines, fusidic acid, for 10 days

Local treatment: antiseptic – local antibiotics, 2x/d for 10 days (may suffice)

Local and general hygiene measures: careful hand washing before and after care, protection by dressing

  • Furonculosis: the recommendations are: wearing loose clothing, rigorous hygiene (daily shower with Chlorhexidine), washing of laundry at 90oC

Collection: at sites in Staphylococcus (patient and family environment) then treatment if positive, fusidic acid or Mupirocin, 2x/d, 10 days/month, for 6-12 months

Anti-antibiotic therapy: general – local treatment

Stop work: in case of a profession with a risk of food contamination



  • It is a dermo-hypodermitis, bacterial, acute, non-necrotizing, most commonly related (85%) to a Group A Streptococcus-hemolytic
  • Different germs are sometimes associated


  • Frequent affection, sex-ratio -1
  • Age: adult (55-65 years), sometimes young adult, rarely child
  • Topography: lower limbs (80%), face
  • Factors favouring:

Locoregional gateway: chronic wound (leg ulcer, surgical wound), inter-toe cracking (mechanical or mycosic), simple trauma to the extremities of the lower limbs

Venous or lymphatic insufficiency of the lower limbs

General factors: diabetes, immunodepression, advanced age


  • Positive diagnosis: clinical , the germ is rarely highlighted (gateway or hemocultures)

Clinical aspects: the usual form of the adult: large, high-red, one-sided febrile leg

  • Start: is brutal, fever high (39-40oC) or even chills, then:

Skin signs: erythemato-edemateous inflammatory skin closet, bright red, warm and painful to palpation, although limited, gradually extending, a peripheral bulge is rare on the leg but common to the face, detachments   superficial bubbles (mechanical consequence of dermal edema) or purpuric lesions

  • Associated signs: inflammatory inguinal adenopathy – digestive signs (diarrhea), there is often a locoregional gateway

Further examinations: often hyperleucocytosis with neutrophil polynucleosis, biological inflammatory syndrome (early high CRP, VS), non-specific Streptococcus serology (ASLO, ASD, ASK), frank rise in inset rates 2-3 weeks tervalle (retrospective diagnosis). In the typical form, no bacteriological examination is required

Clinical forms:

  • Symptomatic: bubble, purpuric, pustular and abscessed forms
  • Topographic:

Face (5-10% of cases): often one-sided and very etematous, with a marked peripheral bulge. More rarely: upper limb, abdomen, chest…

  • Evolutionary (subacute forms): fever and hyperleucocytosis are moderate or absent, diagnosis is based entirely on the clinic and regression on antibiotics
  • Differential diagnosis:

In the face: acute eczema, malignant staphylococcia of the face, ophthalmic shingles

To the limb: phlebitis (sometimes associated), inflammatory flare-up of venous lipodermatosclerosis, acute edema syndrome of the lower limbs, envenomations

Necrotizing Fasciitis: the importance of general toxic signs, the lack of improvement under antibiotic therapy, the local extension of the signs of necrotizing, a crackling require a surgical exploration that ensures the diagnosis


  • Hospitalization: if diagnostic doubt, marked general signs, complications, significant comorbidity, adverse social context, lack of improvement at 72h
  • Means:

Antibiotic therapy: systemic, anti-ptsococcal


Penicillin G: injectable, reference treatment, 10-20 MUI/d in 4-6 infusions

Penicillin V: oral, 4-6 MUI/d in 3 daily intakes

Penicillin A: Oral, Amoxicillin (3-4.5 g/d in 3 daily intakes) as a first-line treatment or relay of Penicillin G after obtaining apyrexia

  • Synergistines: Pristinamycin: 2-3 g/d in 3 daily intakes
  • Clindamycin: 600-1200 mg/d in 3-4 intakes (digestive side effects)
  • Glycopeptides, Augmentin® or Cephalosporins

Adjuvant treatment: strict bed rest (necessary until inflammation regression), preventive anticoagulant therapy (if erysipelas – venous insufficiency of the lower limb), INSAIDs and corticosteroids are formally discouraged ( evolutionary risk to necrotizing fasciitis), analgesic treatment (in case of pain) and appropriate treatment of the front door, elastic restraint (if edema)

  • Indications:

If hospitalization: Penicillin G in IV (at least until apyrexia) then relay per bone (Penicillin V, Amoxicillin). Total time: 10-20 days

If at home: Amoxicillin per bone for about 15 days

  • Pristinamycin (or Clindamycin) with an allergy to lactamines or second-line,

particularly if a staphylococcal etiology is suspected

  • Prevention of recurrences: treatment of a persistent front door and veino-lymphatic deficiency, careful skin hygiene

In case of multiple recurrences: discuss long-term penicillin therapy (Extencillin®: 2.4 MUI im every 2-3 weeks)

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