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Impetigo is a bacterial infection that involves the superficial layer of the skin. It occurs commonly in infants and school-going children; therefore, it is also known as school sores in layman terms. This infection can occur on its own or be preceded by another skin infection that breaks the outermost layer of skin. It is a contagious infection and can spread from one person to another by coming in contact with the site of infection. Impetigo is treatable with the use of suitable antibiotics. 


Impetigo is caused by bacteria residing on our skin surface. Staphylococcus aureus is the primary bacteria that cause this infection. In some cases, Streptococcus pyogenes is involved as well. These bacteria infiltrate the outermost layer of the skin and attack your normal skin cells, triggering your immune system. As a result, the affected skin region may become inflamed or form vesicles. If it continues, the skin breaks open in the affected area, which can cause severe discomfort. Impetigo can also be caused if a breach is already present in the skin due to viral skin infections, eczema, or mosquito bites. 

Risk Factors And Epidemiology

Your immune system is the primary defense against organisms that cause impetigo. A weak immune system can increase the risk of developing this infection. This is why children are more commonly affected by this condition. Children in daycare are more prone to be infected by causative pathogens. Weakened immune due to systemic diseases such as diabetes, leukemia, HIV, etc., also increases the risk. Immunosuppressant medications, chemotherapy, or radiotherapy can also reduce your immune system’s efficiency, raising the risk of contracting impetigo. Trauma or injury resulting from skin cuts or skin abrasions are other factors. Due to this reason, impetigo is also common among athletes and sports personnel. Poor hygiene, dietary insufficiency, and obesity may also be contributing factors. Environmental factors such as high temperature and high humidity can also increase the risk of impetigo.

Impetigo mostly affects children ranging from 2 to 5 years. There is no gender prevalence associated with this infection, and it can occur in both males and females. It is usually observed in tropical regions or areas with a warm, humid climate. 

Signs And Symptoms

The mild to moderate impetigo presents with reddish sores in the initial stage, especially around the nose and lips region. This can spread to other body parts by scratching the infection and touching other regions.  After a few days, the red sores rupture and get replaced by a yellow scab or crust. The lesion is not painful in most conditions, but it can cause itchiness and irritation. Severe cases of impetigo have skin lesions that produce pus discharge. This is a painful condition and may leave scars once the lesions are repaired. Often, impetigo is preceded by another viral or systemic infection, so the history of other symptoms such as fever, malaise, generalized weakness, skin irritation, etc., may be present. 


Impetigo is generally diagnosed based on its clinical presentation. Your doctor will ask questions about the onset, duration, and severity of this infection and whether you had a previous infection or skin disease. History is followed by a clinical examination which involves inspection of the affected skin regions. The presence or absence of pus discharge is also noticed. A gram stain test or culture test may be advised to diagnose the specific type of Staphylococcus aureus, which is antibiotic-resistant. This will help in choosing an effective antibiotic regime.  

Differential Diagnosis

Impetigo needs to be differentiated from other skin conditions that cause sores, redness, itching, or blisters. These conditions include chickenpox, measles, herpes simplex infection, herpes zoster, rubella, insect bites, contact dermatitis, scabies, bullous pemphigoid, erythema multiforme, systemic lupus erythematosus, etc. 


The primary treatment option for impetigo is the use of antibiotics. For mild to moderate cases, topical antibiotics are prescribed. Severe cases of impetigo require intake of oral antibiotics. It is also advised to avoid scratching the lesions because they can spread from your fingertips to other skin regions. For this reason, nails of infected infants or children should be clipped regularly. To limit the spread of this disease from one person to another, it is also suggested to avoid direct contact with an infected person until the course of antibiotics is complete or the lesions heal on their own. Sharing clothes, towels, and other personal use items are also avoided to reduce the risk of its spread. 


Topical antibiotics such as mupirocin, retapamulin, etc., are the first line of treatment. Oral antibiotics such as dicloxacillin, flucloxacillin, amoxicillin, etc., are prescribed in cases of severe impetigo lesions. If the lesions do not recover with these antibiotics, it may be due to the presence of methicillin-resistant staphylococcus aureus (MRSA). Alternative antibiotics such as doxycycline, clindamycin, etc., are prescribed to treat this infection.


Mild cases of impetigo can recover on their own within two to three weeks without any use of medications. Moderate to severe cases recover completely with the prescribed use of an antibiotic regimen. If severe cases are left untreated, they may cause extreme pain and discomfort to the infected person. The infection may spread to cause cellulitis or other systemic complications in rare cases.


The primary method to prevent the incidence of impetigo and to reduce its spread is hand washing. Washing your hands with antibacterial soap or hand-wash is the best way to avoid infections by causative pathogens. The use of hand sanitizer is also effective. Maintenance of personal hygiene, regular showers, and frequent hand-washing is suggested. If you get a skin cut or abrasion, it is best to wash the affected area and cover it with clean gauze. Cuts or abrasions should not be left open because they are highly likely to get infected by the bacteria already present on your skin. Those engaged in sports or other physical activities are advised to wear protective gear to avoid skin damage as much as possible. 


Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on April 28th, 2023.