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Skin Bacterial Infections CS-OSPE

May 27, 20256 min read

Skin Bacterial Infections CS-OSPE

Boil or furuncle

  • If eczema happened around it, itchy = infective eczema

Cellulitis

Case Description/History:

  • There is erythema, edema, and tenderness
  • History of fever, chills, wound

Diagnosis:

  • Cellulitis

Responsible Organism/Cause:

  • Group A streptococcus and Staphylococcus aureus (gram +)

Describe/Characteristics:

  • The subcutaneous tissues are involved and the area is more raised and swollen, and the erythema less marginated.

Differential Diagnosis:

  • Necrotizing fasciitis
  • Superficial Thrombophlebitis
  • Contact dermatitis (CNS)

Superficial Cellulitis:

  • Erysipelas, it’s marked with dermal lymphatic involvement.

Risk Factors:

  1. Local trauma
  2. Underlying skin lesion
  3. Inflammation
  4. Edema and impaired lymphatics in the affected area

Management & Treatment:

  • Full history
  • Examination
  • Education
  • Elevation and rest / Elevation of the area to decrease edema / Elevation of involved area
  • Systemic antibiotics oral or I.V / IV Antibiotic / Systemic Broad spectrum Antibiotic
  • Hospitalization
  • Cold-wet dressing
  • Rest
  • Topical steroids (note: often not primary treatment for cellulitis, but listed in source)

Impetigo

Case Description/History:

  • Facial rash. The rash is not painful, but occasionally burns and itches
  • An 8 Y\O girl with 2 days history of erythema on the upper cutaneous lip extending onto the nose, no elsewhere.
  • This child got this infection from daycare.
  • A five – year - old boy developed vesicles on his face that were not painful or pruritic, but some of the ruptured and crusted.

Diagnosis:

  • Impetigo

Differential Diagnosis:

  • Contact dermatitis
  • Herpes simplex
  • Discoid dermatitis
  • chickenpox
  • measles

Responsible Organisms/Cause:

  • Superficial Bacterial Infection
  • Crusted ulcerated by Group A streptococcus and bullous type by Staphylococcus aureus.

Describe/Morphology:

  • Thin-walled clear .
  • Rupturing to leave area of exudation and yellowish crusting.
  • Papules and plaques with overlying honey- colored crust.
  • Minimal surrounding erythem

Types/Clinical Variants:

  1. Non-bullous impetigo contagiosum (golden appearance)
  2. Bullous impetigo (flaccid bullae with clear yellow fluid, which later becomes purulent)
  3. Ecthyma deep impetigo (“punched out” ulcers covered with yellow crust surrounded by raised margins)

Diagnostic Question:

  • If any one have the same Symptoms of his family / If any one have the same Symptoms in family

Management & Treatment:

  • Full history
  • Examination
  • Education
  • Topical or oral antibiotics

What is the diagnosis?

  • Non-bullous Impetigo (contagiosum).

How does it clinically present?

  • Lesions begin as papules surrounded by erythema.
  • They progress to form pustules that enlarge and break down to form thick, adherent crusts with a characteristic golden appearance.

What are the key pathological agents and their characteristics?

  • Staphylococcus aureus: cleaves cell adhesion molecules, often associated with bullous forms.
  • Streptococci pyogenes: commonly results in crusted, ulcerated lesions.

What is the recommended treatment?

  • For localized lesions?
    • Topical antibiotics.
  • For widespread lesions or more severe infection?
    • Oral Flucloxacillin/Erythromycin.
  • What general measures are recommended?
    • Hand washing to reduce spread.
    • Wash the affected area with antibacterial soap.

Bullous Impetigo

Diagnosis:

  • Bullous Impetigo

Clinical Presentation:

  • flaccid bullae with clear yellow fluid, which later becomes purulent.
  • Ruptured bullae leave a thick brown crust

Pathology:

  • Staphylococcus aureus: cleave the cell adhesion molecule = bullous.
  • Streptococci pyogenes: crusted ulcerated.

Treatment: For localized lesions:

  • Topical antibiotics. For widespread lesions or more severe infection:
  • Oral Flucloxacillin/ Erythromycin.
  • Hand washing to reduce spread.
  • Wash the affected area with antibacterial soap.

Ecthyma

Diagnosis

  • Ecthyma (deep impetigo).

Clinical Presentation

  • Ulcers forming under a crusted surface infection.
  • Ulcer is full thickness and heals with scarring and pigmentation.

Pathology

  • Staphylococcus aureus
  • Streptococci

Treatment

  • For localized lesions:
    • Topical antibiotics.
  • For widespread lesions or more severe infection:
    • Oral Flucloxacillin/ Erythromycin.
  • Hand washing to reduce spread.
  • Wash the affected area with antibacterial soap.

Secondary Syphilis

Secondary Syphilis

Erythema Nodosum

What is the diagnosis?

  • Erythema nodosum

What are two diseases associated with Erythema Nodosum?

  • Panniculitis
  • Crohn’s disease

Clinical Presentation

  • Multiple, bilateral, erythematous nodules typically found in the shins.

Pathology

  • Characterized by panniculitis (inflammation of the subcutis).
  • Can be idiopathic or a reaction to infections, medications, or an underlying autoimmune disease (e.g., Crohn’s disease).

Treatment

  • The condition is often self-limited.
  • Painkillers can be administered for symptomatic relief.

Panniculitis

What is the name of this condition?

  • Panniculitis

Mention one condition that could be associated with this condition?

  • Addison disease

Folliculitis

What is the diagnosis?

  • Folliculitis.

What is the clinical presentation?

  • Painless or tender pustule that eventually heals without scarring.

What is the pathology/causative agent?

  • Staphylococcus aureus.

What is the treatment?

  • Solitary small furuncle: warm compresses to promote drainage may be sufficient.
  • Localized lesions:
    • Antiseptics or
    • Topical antibiotics.
  • Widespread lesions or more severe infection:
    • Oral Erythromycin.
  • Stop shaving that area.
  • Wash the area daily (antibacterial soap may be used).

Carbuncle

What is the diagnosis?

  • Carbuncle.

What is the clinical presentation?

  • Purulent material from a multiple opening.
  • Swollen painful suppurating area discharging pus from several points.

What is the pathology?

  • Staphylococcus aureus.

What is the treatment?

  • Incision & drainage (I&D) +
  • Oral Flucloxacillin +
  • Topical antibiotic.

Abscess

What is the diagnosis?

  • Abscess.

What is the clinical presentation?

  • Erythematous, warm, fluctuant nodule with several small pustules throughout the surface.
  • Very tender to palpation.

What is the pathology?

  • Staphylococcus aureus.

What is the recommended treatment?

  • Incision & drainage.
  • Oral Flucloxacillin.
  • Offer HIV test.

Sycosis barbae

What is the diagnosis?

  • Sycosis barbae.

What is the clinical presentation?

  • follicular papules or pustules.

What is the causative agent?

  • Staphylococcus aureus.

What is the recommended treatment?

  • For localized lesions: Topical antibiotics.
  • For widespread lesions or more severe infection: Oral Flucloxacillin.

Paronychia

Diagnosis:

  • Paronychia.

Clinical Presentation:

  • Bright red swelling of the proximal and lateral nailfold.
  • Painful.
  • Rapid onset.

Pathology:

  • Staphylococcus aureus.

Treatment:

  • Warm water compresses.
  • Topical or systemic antistaphylococcal antibiotic.

Erysipelas

What is the diagnosis?

  • Erysipelas.

What are the clinical presentations?

  • Presents with pain, superficial erythema, and plaque-like edema with a sharply defined margin to normal tissue. Plaques may develop overlying blisters (bullae).

What is the pathology?

  • Group A streptococci.

What is the treatment?

  • Oral Flucloxacillin.

Staphylococcal scalded skin Syndrome SSSS (Ritter’s disease)

What is the diagnosis?

  • Staphylococcal scalded skin Syndrome (SSSS), also known as Ritter’s disease.

What is the clinical presentation?

  • Erythema and tenderness, followed by the loosening of large areas of overlying epidermis.
  • Fluid from bullae is sterile.

What is the pathology?

  • Caused by Staphylococcus aureus.
  • Leads to acute skin failure.

What is the treatment?

  • Admission to a severe burn unit, which involves:
    • Nursing care.
    • Monitoring hemodynamic changes.
    • Maintaining fluid, electrolyte balance, and nutrition.
    • Prevention of complications (e.g., sepsis).
    • Identification of risk factors.
    • Topical therapy.
  • Oral or IV flucloxacillin.
  • The patient’s skin should be lubricated with light lotions.

Necrotizing Fasciitis

What is the diagnosis?

  • Necrotizing Fasciitis.

What is the clinical presentation?

  • Ill-defined, large erythematous plaque with central patches of dusky blue discoloration, which is anesthetic.
  • Upon re-examination 60 minutes later, the redness had spread.

What are the common pathogens?

  • Staphylococcus aureus.
  • Group A streptococci.

What is the recommended treatment?

  • Call an urgent surgery consult.
  • Give IV fluids and antibiotics.
  • Image with stat MRI.
  • Obtain a deep skin biopsy.
  • Treatment includes widespread debridement and broad-spectrum systemic antibiotics.

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