Impetigo

Impetigo
Classification and external resources
Facial impetigo
ICD-10	L01
ICD-9	684
DiseasesDB	6753
MedlinePlus	000860
eMedicine	derm/195 emerg/283 med/1163 ped/1172
MeSH	D007169

Impetigo /ɪmpɨˈtaɪɡoʊ/ is a highly contagious bacterial skin infection most common among pre-school children.^[1] People who play close contact sports such as rugby, American football and wrestling are also susceptible, regardless of age. Impetigo is not as common in adults. The name derives from the Latin impetere ("assail"). It is also known as school sores.^[2]

Classification

Impetigo on the neck

Impetigo contagiosa

This common form of impetigo, also called nonbullous impetigo, most often begins as a red sore near the nose or mouth which soon breaks, leaking pus or fluid, and forms a honey-colored scab, followed by a red mark which heals without leaving a scar. Sores are not painful, but may be itchy. Lymph nodes in the affected area may be swollen, but fever is rare. Touching or scratching the sores may easily spread the infection to other parts of the body.^[3] Ulcerations with erythema and scarring also may result from scratching or abrading of the skin.

Bullous impetigo

Bullous impetigo

Bullous impetigo, mainly seen in children younger than 2 years, involves painless, fluid-filled blisters, mostly on the arms, legs and trunk, surrounded by red and itchy (but not sore) skin. The blisters may be large or small. After they break, they form yellow scabs.^[3]

Ecthyma

In this form of impetigo, painful fluid- or pus-filled sores with redness of skin, usually on the arms and legs, become ulcers that penetrate deeper into the dermis. After they break open, they form hard, thick, gray-yellow scabs, which sometimes leave scars. Ecthyma may be accompanied by swollen lymph nodes in the affected area.^[3]

Causes

It is primarily caused by Staphylococcus aureus, and sometimes by Streptococcus pyogenes.^[4] According to the American Academy of Family Physicians, both bullous and nonbullous are primarily caused by Staphylococcus aureus, with Streptococcus also commonly being involved in the nonbullous form."^[5]

Transmission

The infection is spread by direct contact with lesions or with nasal carriers. The incubation period is 1–3 days after exposure to Streptococcus and 4–10 days for Staphylococcus.^[6] Dried streptococci in the air are not infectious to intact skin. Scratching may spread the lesions.

Diagnosis

Impetigo generally appears as honey-colored scabs formed from dried serum, and is often found on the arms, legs, or face.^[4]

Treatment

For generations, the disease was treated with an application of the antiseptic gentian violet.^[7] Today, topical or oral antibiotics are usually prescribed. Treatment may involve washing with soap and water and letting the impetigo dry in the air. Mild cases may be treated with bactericidal ointment, such as mupirocin, which in some countries may be available over-the-counter. More severe cases require oral antibiotics, such as dicloxacillin, flucloxacillin or erythromycin. Alternatively amoxicillin combined with clavulanate potassium, cephalosporins (1st generation) and many others may also be used as an antibiotic treatment.

Epidemiology

Globally impetigo affected approximately 140 million people (2% of the population) in 2010.^[8]

References

Notes

External links

• Impetigo Pictures — Pictures of Impetigo caused by Staph Infections and MRSA.
• NIH/Medline
• Photos (University of Iowa)
• Dermnet NZ
• Impetigo and Ecthyma at Merck Manual of Diagnosis and Therapy Professional Edition