Types of Impetigo

Doctors recognise three main forms of impetigo, which differ in appearance and cause.

Non-bullous impetigo

• The most common form, about 7 in 10 cases
• Caused by Staphylococcus aureus or group A Streptococcus
• Small red sores that burst and form honey-coloured crusts
• Mostly around the nose, mouth and on exposed skin

Bullous impetigo

• Caused by Staphylococcus aureus that produces a toxin
• Large, thin-walled blisters filled with clear or yellow fluid
• Mostly on the trunk, buttocks and skin folds
• More common in infants and young children

Ecthyma

• A deeper, more serious form that reaches below the top skin layers
• Punched-out, painful ulcers with thick crusts
• More likely on the legs, in people with poor hygiene, diabetes or weak immunity
• Can leave scars

Primary and secondary impetigo

• Primary: appears on previously healthy skin.
• Secondary: appears on skin already damaged by eczema, scabies, bites or cuts. It is also called impetiginisation.

Related conditions

Staphylococcal scalded skin syndrome is a more serious, toxin-related illness in babies and young children and needs urgent care.

Ayurvedic view

Traditional texts do not separate these types. Any matching is interpretive only.

Key point

The type guides treatment. Widespread or bullous forms, and any case in a newborn, need a doctor's review.

Before your appointment

Note when the sores began, where they started, whether they ooze or crust, and whether anyone at home or school has similar sores. List any fever, itching, eczema, scabies, diabetes, allergies and medicines tried so far. Take a photo of the rash. Ask about the antibiotic, when it is safe to return to school and the warning signs that mean you should call 112 or 102.