Bullous vs Non-Bullous Impetigo: Key Differences Explained

Impetigo is a highly contagious bacterial skin infection, most common in young children but also possible in adults.

Usually caused by Staphylococcus aureus or Streptococcus pyogenes, it produces sores, blisters or characteristic golden-brown crusts and spreads easily through close contact.

There are two main types: bullous and non-bullous impetigo. So, what separates them and does treatment differ?

Non-Bullous vs Bullous Impetigo [Quick Comparison]

What Is Bullous Impetigo?

Bullous impetigo is the less common (about 30% of the cases) blister-forming type of impetigo.

It is caused by particular strains of Staphylococcus aureus that release toxins affecting the proteins that hold cells together in the outer layer of the skin.

This causes the skin layers to separate and produces the characteristic larger, fragile blisters, known as bullae.

What Causes Bullous Impetigo?

Unlike non-bullous impetigo, which can involve either S. aureus or S. pyogenes, bullous impetigo is caused by toxin-producing S. aureus.

These exfoliative toxins damage connections between cells near the skin's surface, allowing fluid to collect and form blisters. Bullous impetigo can also develop on previously intact skin.

Symptoms of Bullous Impetigo

Look out for:

• Larger, fluid-filled blisters
• Blisters that quickly enlarge and easily burst
• Yellow fluid leaking from broken blisters
• A thin, scaly rim around ruptured blisters
• Itching
• Fever or feeling generally unwell in some cases
• Swollen lymph nodes in some people

Where Does Bullous Impetigo Usually Appear?

Bullous impetigo can develop anywhere on the body, but it commonly affects warm, moist areas and skin folds. Typical locations include:

• The trunk, particularly the abdomen
• The armpits
• The groin and nappy area
• The arms and legs
• The face

What Is Non-Bullous Impetigo?

Non-bullous impetigo is the most common form of the infection (70% of the cases). It usually begins with small red sores, pustules or blisters. These quickly burst, leaving moist areas that develop the recognisable golden-brown or honey-coloured crust.

What Causes Non-Bullous Impetigo?

Non-bullous impetigo can be caused by Staphylococcus aureus, Streptococcus pyogenes, or both.

Unlike bullous impetigo, toxin production is not responsible for its characteristic appearance. Bacteria often enter through damaged skin, including cuts, scratches and insect bites. Existing skin conditions can also weaken the skin barrier. For example, scratching eczema may make bacterial infection easier.

Read also: Winter Eczema: Calm Flare-Ups with These Tips.

Symptoms of Non-Bullous Impetigo

Common signs include:

• Small red sores, pustules or blisters
• Sores that quickly burst
• Golden-brown or honey-coloured crusts
• Mild itching
• Swollen nearby lymph nodes in some cases

Where Does Non-Bullous Impetigo Usually Appear?

Non-bullous impetigo most commonly develops on exposed areas of skin, particularly the face around the nose and mouth. This is one of the most recognisable patterns of the infection.

Other common areas include:

• The hands and arms
• The legs
• Areas around cuts, scratches or insect bites

Because impetigo is contagious, scratching or touching infected sores can transfer the bacteria and cause new patches elsewhere on the body.

Non-Bullous vs Bullous Impetigo Treatment

Treatment for Non-Bullous Impetigo

• Localised non-bullous impetigo: If you are otherwise well and the infection affects a small area, hydrogen peroxide 1% cream may be recommended. Hydrogen peroxide acts as an antiseptic, helping to kill bacteria on the skin and control the infection. If this is unsuitable or has not worked, a healthcare professional may prescribe a short course of a topical antibiotic.
• Widespread non-bullous impetigo: A short course of either a topical or oral antibiotic may be prescribed. The choice depends on factors such as how extensive the infection is and whether applying a topical treatment to all affected areas would be practical.

Treatment for Bullous Impetigo

Bullous impetigo generally requires a short course of an oral antibiotic, rather than treatment with hydrogen peroxide or a topical antibiotic alone. Oral antibiotics are also recommended for people with any form of impetigo who are systemically unwell or at higher risk of complications.

Do not rely on appearance alone to decide which type of impetigo you have. A pharmacist or other healthcare professional can assess the impetigo rash and recommend the most appropriate treatment.

For more information about symptoms, causes, prevention and how the infection spreads, read our complete guide to impetigo!

Bullous vs Non-Bullous Impetigo — Conclusion

Bullous and non-bullous impetigo are contagious bacterial infections, but they differ in their appearance, bacterial causes and treatment.

Getting the correct diagnosis matters, particularly when blisters are widespread or you feel unwell.

For professional assessment and appropriate care, access Weldricks’ impetigo treatment service!