Pustular Skin Lesions - Differential Diagnosis Framework



What are pustules?

• Pustules < 5-10 mm + pus

• Material composed of inflammatory cells (neutrophils)

• Pus --> bacterial, fungal, or viral infection

• Some pustules are sterile and are due to inflammatory skin disease



Pustular Localised Eruptions (Face/Scalp):

1. Impetigo

2. Furunculosis/boil

3. Folliculitis

4. Dermatophyte infection

5. Kerion

Inflammatory, pus-filled sore (abscess) that sometimes oozes:

1. Thrush/Candidal intertrigo

2. Herpes zoster

3. Herpes simplex

4. Pityrosporum/Malassezia folliculitis

5. Rosacea



Pustular Diffuse Eruptions (Trunk):

1. Acne vulgaris

2. Acneiform eruptions

3. Miliaria

4. Scabies

    • Irregular pustules on hands and feet

    • Burrows between fingers, volar wrists

    • Papules axillae, groin

    • Generalized itchy rash

5. Dermatophyte infection

6. Palmoplantar pustulosis

7. Erosive pustular dermatosis

8. Hidradenitis suppurativa

9. Bacterial folliculitis/hot tub folliculitis

10. Fire ant bites

11. Pustular psoriasis (GPP)

12. Subcorneal pustular dermatosis (Sneddon-Wilkinson disease)

13. Mpox

    • Starts on face --> spreads to trunk

    • Pustules >> look like bumps >> blisters that eventually scab over.

14. SAPHO syndrome (synovitis, acne, pustulosis, osteitis) - Pustular skin disease in association with rheumatic pain.

15. Pustular Eczema



Pustules + Fever:

1. Eosinophilic folliculitis

2. Varicella

3. Acute generalized exanthematous pustulosis

    • Febrile illness

    • Drug eruption

    • Diffuse superficial pustules

4. Disseminated gonococcemia

5. Secondary syphilis

6. Pustular psoriasis (GPP)

7. Pyoderma gangrenosum

8. Sweet syndrome



#Pustular #Skin #Lesions #Differential #Diagnosis #Dermatology