Pustules are circumscribed collections of white blood cells and serous fluid. Many skin lesions will present with papules or vesicles (clear fluid); those presenting with pustules occur less frequently. It is important to recognize the morphological pattern of pustules because it may imply a different spectrum of differential diagnosis as well as treatment.
While the differential diagnosis of pustules is broad (table 1), most diagnoses seen by primary care physicians will fit one of the diseases below. Several defining features can aid in narrowing down the possibilities in an efficient manner:
- The patient's age and general health
- The distribution of lesions
- The duration of the lesions
Simple procedures can confirm the diagnosis when questions persist.
Acne rosacea — Acne rosacea is a disease in healthy adults that may present with pustular eruptions, particularly in moderate and severe cases. Pustular rosacea is found frequently on the central face, neck, and occasionally trunk. Look for telangiectasia, erythema, papules, nodules, thickening of the soft tissue, and sebaceous prominence of the central face (picture 1A-C). Historically rosacea worsens with alcohol, spicy food, temperature extremes, and stress. (See "Rosacea: Pathogenesis, clinical features, and diagnosis".)