What causes impetigo

What is Impetigo?

Impetigo is a common and highly contagious bacterial skin infection that primarily affects infants and young children. It typically appears as red sores on the face, especially around a child's nose and mouth, and on hands and feet. These sores quickly rupture, ooze, and then form a yellowish-brown crust, often described as resembling honey or brown sugar. While it can occur in adults, it's far more prevalent in children aged 2 to 5 years old.

What Causes Impetigo?

The root cause of impetigo lies in bacterial invasion of the skin. The two main types of bacteria responsible are Staphylococcus aureus (staph) and Streptococcus pyogenes (group A strep). These bacteria are ubiquitous and commonly found on the skin and in the nose of many healthy people without causing any problems. However, they can cause infection when they gain entry into the body through a break in the skin.

Entry Points for Bacteria

The skin acts as a protective barrier, but several common occurrences can compromise this defense:

• Minor Cuts, Scrapes, and Abrasions: Even the smallest injury to the skin can provide an opening for bacteria.
• Insect Bites: Bites from mosquitoes, fleas, or other insects can break the skin and become infected.
• Eczema and Other Skin Conditions: Pre-existing skin conditions like eczema, psoriasis, or dermatitis can weaken the skin's barrier, making it more susceptible to bacterial infection.
• Chickenpox Scabs: Scratching chickenpox lesions can introduce bacteria into the broken skin.
• Allergic Reactions: Rashes from allergies can also create opportunities for bacteria.

Types of Impetigo and Their Causes

There are two main forms of impetigo, each linked to the specific bacteria involved:

1. Non-bullous Impetigo (Most Common)

This is the most frequent type, accounting for roughly 70% of all impetigo cases. It typically starts as small red spots that quickly turn into tiny blisters or pustules. These lesions then break open, leaving behind moist, red sores. As they heal, they develop the characteristic yellowish-brown crust. This form is most commonly caused by Staphylococcus aureus, but Streptococcus pyogenes can also be responsible.

2. Bullous Impetigo

This less common form is almost always caused by Staphylococcus aureus. It is characterized by larger, fluid-filled blisters (bullae) that form on intact skin, usually on the trunk, arms, and legs. These blisters typically don't have a preceding red spot. They tend to be painless and may take longer to rupture than the smaller sores of non-bullous impetigo. Once they break, they leave behind a thinner, lighter-colored crust.

Factors Increasing Risk

While anyone can develop impetigo, certain factors can increase the likelihood of infection:

• Age: As mentioned, children between 2 and 5 years old are most susceptible due to their developing immune systems and tendency to get scrapes and cuts.
• Environment: Impetigo thrives in warm, humid conditions. It is also more common in settings where people are in close contact, such as schools, daycare centers, and sports teams.
• Season: Outbreaks are often more common during the summer months when skin injuries from playing outdoors are more frequent.
• Hygiene: Poor personal hygiene can contribute to the spread of bacteria.
• Compromised Skin Barrier: Conditions that damage the skin's natural defenses, like eczema, psoriasis, or even shaving, make individuals more vulnerable.
• Contagious Nature: Impetigo is highly contagious. It spreads easily through direct contact with the fluid from the sores, or indirectly through contact with contaminated items like towels, clothing, bedding, and toys. Sharing personal items is a primary way the infection is transmitted.

Prevention and When to Seek Medical Advice

Preventing the spread of impetigo involves good hygiene practices, such as frequent handwashing and keeping cuts and scrapes clean and covered. If you suspect you or your child has impetigo, it's important to consult a healthcare professional for diagnosis and appropriate treatment, which typically involves topical or oral antibiotics.