Reuben Notes

Papulosquamous Diseases


  • Chronic, inflammatory rash with increased and rapid epidermal proliferation resulting in accumulation of stratum corneum
  • Classic lesion: Well-circumscribed, erythematous plaque with a dry, silvery scale appearing on extensor surfaces of the limbs.
    • Lesions are bilateral and symmetrical in distribution.
  • Most commonly on extensor surfaces (knees, elbows, nails)
  • Presents as erythematous patches and plaques covered with white scales
  • Associated with "Auspitz" sign - Tugging gently on scale results in pinpoint bleeding
  • Associated with arthritis, classically sero-negative and exhibiting a predilection for the distal inter-phalangeal joints
  • Guttate Psoriasis
    • Guttate - Latin for "drop-like."
    • SImilar in color and texture but shaped like drops or smaller circular lesions than in the classic form
  • Pustular Psoriasis
    • Multiple, fresh, yellow pustules AND older, dry, brown macules on the palms and soles
    • Classically mis-diagnosed as vesicular tinea pedis.
  • Psoriatic Nail disease
    • "oil-drop" staining
    • pitting - small depressions on the surface of the nail plate
    • Sub-ungual debris and hyperkeratosis
    • Transverse grooves
    • Looks similar to onychomycosis and my coexist with onychomycosis


Bacterial Infections of the skin


  • A superficial skin infection due to S. Pyogenes & S. aureus, alone or together. Especially common in children in hot, humid climates
  • Small, thin-walled vesicles or pustules on an erythematous base rupture to form characteristic yellow-brown (honey-colored) crusts.  Removal of the crusts reveal a superficial, moist base.  Lesions do not ulcerate.
  • Commonly found on the face and extremities
  • Involved areas may be pruritic.  Regional lymph node involvement is common but other systemic manifestations are rare.
  • Treatment:
    • Topical antibiotics (Mupirocin, Bacitracin, Neomycin)
    • Systemic Antibiotics (Dicloxicillin, Clindamycin)



  • A superficial skin infection caused by Group A Strep and S. Aureus
  • Begins as vesicles or bullae that rupture to form cursts.  Removal of crust reveals an ulceration.  Heals with scarring
  • Lesions are typically erythematous, circular, and multiple.  Most commonly involve the lower extremities.
  • Treatment:
    • Oral antibiotics (Dicloxacillin)


Erysipelas and Cellulitis

  • When a Strep infection spreads into the dermal lymphatics, erysipelas occurs and when it involves the deeper dermis and subcutaneous fat, cellulitis occurs.
  • S. Pyogenes releases enzymes to facilitate rapid spread of the infection through tissue planes and prevent abscess formation.  Edema, erythema, and heat develop.  The enzymes also produce systemic manifestations (fever, tachycardia, confusion, and hypotension)
  • Predisposing factors: edema, tinea pedis, previous trauma to skin - burns, surgery, or radiation.
  • Most common sites are the face of lower extremities
  • Erysipelas unlike cellulitis has a sharply demarcated and elevated border.
  • Both needle aspiration and skin biopsy of the lesion usually fail to yield organisms
  • Causitive agents: Usually Strep
    • S. aureus - around abscess or open wound
    • H influenzae - facial cellulitis in young children (6-36 months)
    • P. Multocida - cat and dog bites
    • P. aeroginosa & other gram (-) organisms - common in immunocompromised hosts
  • Treatment: Mild - oral antibiotics
    • Severe - IV antibotics
    • Signs and symptoms may worsen after therapy is initiated because the antimicrobial rapidly kills the bacteria causing the release of potent enzymes.


Furuncles and Carbuncles

  • A furuncle is an infection of the hair follicle that produces an inflammatory nodule with a pustule center through which the hair emerges.
  • A Carbuncle affects several adjacent hair follicles and begins as a nodule which enlarges to create an inflammatory mass that discharges pus from multiple follicular orifices.  They occur predominantly on the back of the neck and is more common in diabetics.
  • S. aureus is the most common cause of both.
  • Treatment:
    • Small furuncles - moist heat to promote drainage
    • Carbuncles and Large Furuncles - Incision and Drainage



  • Inflammation at the opening of the hair follicle.  Pathogenesis involves......