II. Pathophysiology
- Typically develop from Vesicles or bullae that fill with pus, or from Hair Follicles or Sweat Glands
- May also spontaneous form a non-follicular Pustule
III. Description
- Raised, translucent superficial, circumscribed skin lesion
- Contains purulent exudate (white, orange, yellow, green)
- Follicular Pustules are conical with hair in center
- Non-follicular Pustules vary in shape
IV. Differential Diagnosis: Hemorrhagic Pustules (or Necrotic Pustules)
- Disseminated Gonococcal Infection (esp. Palm and Sole Pustules)
- Septic Shock (with Disseminated Intravascular Coagulation)
- Disseminated Nocardia
- Pyoderma Gangrenosum
- Smallpox
- Ecthyma gangrenosum
V. Labs
- Gram Stain and culture of pustular discharge (exclude Disseminated Gonorrhea)
VI. Examples
- Drug Eruption
- Acne Vulgaris
- Generalized Pustular Psoriasis syndrome
- Viral vessicular eruptions may develop into Pustules (e.g. varicella, Herpes Zoster virus, Herpes Simplex Virus)