Overview

Impetigo is a common and highly contagious skin infection that primarily affects infants and young children, although it can occur at any age.¹ It is also commonly called ‘school sores’ because it spreads among school-aged children faster. What do you do if your child comes home with sores around their face and arms that you cannot identify? 

Impetigo often manifests as red sores that quickly rupture, ooze for a few days, and then form a distinctive honey-coloured crust.² Recognizing these symptoms early is crucial for effective treatment and to prevent the spread to others. This article shows you everything you need to know about impetigo and what to do.

What is impeitigo? 

Definition

Impetigo is a common, highly contagious bacterial skin infection that primarily affects infants and young children, though it can occur in individuals of all ages.¹ It is caused by two types of bacteria: Staphylococcus aureus and Streptococcus pyogenes.³ The infection typically manifests as red sores or blisters that burst and form a characteristic honey-coloured crust.² Impetigo often appears around the nose and mouth but can spread to other parts of the body through direct contact or contaminated items. While impetigo is generally not severe, it can lead to complications if left untreated, such as deeper skin infections or post-streptococcal glomerulonephritis (a kidney condition).⁴ Prompt diagnosis and treatment are essential to manage symptoms and prevent the spread of the infection.

Causes

Impetigo is primarily caused by bacterial infections,³ with the most common culprits being:

• Staphylococcus aureus: This bacterium is the leading cause of impetigo. It can infect healthy skin directly or enter through a break in the skin, such as a cut, insect bite, or other skin trauma
• Streptococcus pyogenes (Group A Streptococcus): This bacterium can also cause impetigo, either on its own or in combination with Staphylococcus aureus. It often leads to the non-bullous form of impetigo

How the infection spreads

• Direct Contact: Impetigo is highly contagious and spreads easily through direct skin-to-skin contact with an infected person⁵
• Contaminated Objects: The bacteria can survive on items like towels, clothing, bedding, and toys, which can then transfer the infection to others who touch these contaminated objects⁴
• Scratching: Scratching an infected area can also spread the bacteria to other parts of the body or to other people

Impetigo can also develop as a secondary infection from insect bites, cuts and scrapes, and other skin infections.⁶

Types of Impetigo

There are two main types of impetigo: non-bullous (crusted) impetigo and bullous impetigo.

Non-Bullous (Crusted impetigo)

Non-bullous impetigo is the more common type, accounting for about 70% of cases.⁷ It begins as small red sores or pimples, usually around the nose and mouth, but can spread to other parts of the body. These sores quickly burst, releasing a clear fluid or pus. The fluid dries, forming a thick, honey-coloured crust over the sores.² The affected areas can be itchy and occasionally painful. New sores can develop around the initial site, leading to a spreading rash if scratched or touched.

Non-bullous impetigo is primarily caused by Staphylococcus aureus and sometimes Streptococcus pyogenes.³ It often occurs after minor skin injuries such as cuts, insect bites, or other skin conditions like eczema. It is highly contagious, spreading through direct contact with infected sores or contaminated items such as towels, bedding, or clothing.

Bullous Impetigo

Bullous impetigo is less common and primarily caused by Staphylococcus aureus, which produces toxins that lead to blister formation.⁸ It is characterized by larger fluid-filled blisters (bullae) that can appear on the torso, arms, and legs.⁹ These blisters can range from a few millimetres to several centimetres in diameter. These blisters are fragile and can easily rupture, leaving behind red, raw skin.

Unlike non-bullous impetigo, bullous impetigo has less crust formation and more prominent blistering.⁹ The blisters may be itchy and painful, causing discomfort.

Bullous impetigo is exclusively caused by Staphylococcus aureus, which produces toxins that cause the skin layers to separate and form blisters.¹⁰ Like the non-bullous type, it is also highly contagious, with transmission occurring through direct contact with the blisters or fluid, as well as contaminated objects.

Common symptoms of impetigo

Initial symptoms

• Red Sores or Pimples: Impetigo often starts with small red sores or pimples, particularly around the nose and mouth. These can also appear on other parts of the body, especially the hands and feet
• Itchiness: The initial sores may be itchy, prompting scratching which can exacerbate the spread of the infection
• Swelling and Redness: The skin around the sores may become swollen and red, indicating inflammation

Progressive symptoms

• Bursting Sores: The initial red sores quickly burst, releasing a clear fluid or pus. This fluid is highly contagious and can spread the bacteria to other areas of the skin or to other individuals
• Crust Formation: After the sores burst, they dry out and form thick, honey-coloured crusts. This crust is a hallmark of impetigo and makes the infection easily recognizable
• Spreading Rash: Without treatment, the infection can spread, leading to additional sores and crusts in other parts of the body
• Discomfort and Pain: As the infection progresses, the affected areas can become more painful and uncomfortable, especially if there is significant itching and scratching

Symptoms according to types

How is Impetigo different from other sores?

1. Appearance and Crust Formation: Unlike other sores or skin conditions, impetigo sores have a unique honey-colored crust. Other skin conditions may scab over, but they typically do not form the same distinctive crust. Eczema, for instance, usually involves dry, scaly patches rather than honey-colored crusts. Herpes simplex virus sores (cold sores) typically appear as grouped blisters on a red base and then form scabs rather than crusts
2. Location and Spread: Impetigo often starts around the nose and mouth, although it can spread to other areas. While other conditions like eczema or insect bites can occur anywhere, the clustering of sores around the facial area is a notable sign of impetigo. The rapid spread of impetigo sores is another distinguishing factor. Conditions like acne or fungal infections spread more slowly
3. Fluid-Filled Blisters: In bullous impetigo, the presence of large, fluid-filled blisters is a key identifier. These blisters can be several centimeters in diameter and are not typically seen in other common skin infections. Conditions like chickenpox also have fluid-filled blisters, but chickenpox blisters are usually smaller and appear in waves over the entire body

When to seek medical care

1. If you suspect that you or your child has impetigo based on the characteristic symptoms of red sores, blisters, and honey-colored crusts,
2.  If the symptoms of impetigo worsen despite home care measures, such as the spread of sores to other parts of the body, increasing pain or discomfort, or signs of systemic illness like fever or swollen lymph nodes, medical attention is warranted.
3.  Impetigo, if left untreated, can lead to complications such as cellulitis (a deeper skin infection), post-streptococcal glomerulonephritis (a kidney condition), or scarlet fever. If you notice signs of these complications, such as persistent fever, joint pain, or difficulty urinating, seek prompt medical care.
4.  Since impetigo is highly contagious, seeking medical care can help prevent the spread of the infection to others, especially in settings like schools, daycare centers, or workplaces where close contact is common.
5.  If you or your child experience frequent or recurrent episodes of impetigo, it's advisable to consult a healthcare professional for further evaluation and management to prevent future occurrences.

Impetigo is typically treated with a combination of topical and/or oral antibiotics, along with good hygiene practices.^4,11

FAQ’s

How is impetigo treated?

Treatment for impetigo usually involves topical and/or oral antibiotics to kill the bacteria causing the infection. Good hygiene practices, such as keeping the affected areas clean and dry, are also important.

How long does it take for impetigo to heal?

With proper treatment, impetigo usually heals within 1 to 2 weeks. Completing the full course of antibiotics is important to ensure the infection is fully eradicated.

Can impetigo recur?

Yes, impetigo can recur, especially without proper hygiene measures or close contact with infected individuals. Practising good hygiene and avoiding sharing personal items can help reduce the risk of recurrence.

Can impetigo lead to complications?

While impetigo is generally not serious, it can lead to complications if left untreated, such as cellulitis, post-streptococcal glomerulonephritis, or the spread of infection to other parts of the body.

Summary

Impetigo, although a highly contagious skin infection that occurs mostly in children, can be managed properly if it is detected early and if personal hygiene measures are put in place. Your ability to recognize it early and determine how well it is managed.