Impetigo (redirected from impetigo contagiosa)

Impetigo 

Definition

Impetigo refers to a very localized bacterial infection of the skin. There are two types, bullous and epidemic.

Description

Impetigo is a skin infection that tends primarily to afflict children. Impetigo caused by the bacterium Staphylococcus aureus (also known as staph) affects children of all ages. Impetigo caused by the bacteria called group A streptococci (also know as strep) are most common in children ages two to five.

The bacteria that cause impetigo are very contagious. They can be spread by a child from one part of his or her body to another by scratching, or contact with a towel, clothing, or stuffed animal. These same methods can pass the bacteria on from one person to another.

Impetigo tends to develop in areas of the skin that have already been damaged through some other mechanism (a cut or scrape, burn, insect bite, or vesicle from chickenpox).

Causes and symptoms

The first sign of bullous impetigo is a large bump on the skin with a clear, fluid-filled top (called a vesicle). The bump develops a scab-like, honey-colored crust. There is usually no redness or pain, although the area may be quite itchy. Ultimately, the skin in this area will become dry and flake away. Bullous impetigo is usually caused by staph bacteria.

Epidemic impetigo can be caused by staph or strep bacteria, and (as the name implies) is very easily passed among children. Certain factors, such as heat and humidity, crowded conditions, and poor hygiene increase the chance that this type of impetigo will spread rapidly among large groups of children. This type of impetigo involves the formation of a small vesicle surrounded by a circle of reddened skin. The vesicles appear first on the face and legs. When a child has several of these vesicles close together, they may spread to one another. The skin surface may become eaten away (ulcerated), leaving irritated pits. When there are many of these deep, pitting ulcers, with pus in the center and brownish-black scabs, the condition is called ecthyma. If left untreated, the type of bacteria causing this type of impetigo has the potential to cause a serious kidney disease called glomerulonephritis. Even when impetigo is initially caused by strep bacteria, the vesicles are frequently secondarily infected with staph bacteria.

Impetigo is usually an uncomplicated skin condition. Left untreated, however, it may develop into a serious disease, including osteomyelitis (bone infection), septic arthritis (joint infection), or pneumonia. If large quantities of bacteria are present and begin circulating in the bloodstream, the child is in danger of developing an overwhelming systemic infection known as sepsis.

Diagnosis

Characteristic appearance of the skin is the usual method of diagnosis, although fluid from the vesicles can be cultured and then examined in an attempt to identify the causative bacteria.

Treatment

Uncomplicated impetigo is usually treated with a topical antibiotic cream called mupirocin. In more serious, widespread cases of impetigo, or when the child has a fever or swollen glands, antibiotics may be given by mouth or even through a needle placed in a vein (intravenously).

Prognosis

Prognosis for a child with impetigo is excellent. The vast majority of children recover quickly, completely, and uneventfully.

Prevention

Prevention involves good hygiene. Handwashing; never sharing towels, clothing, or stuffed animals; and keeping fingernails well-trimmed are easy precautions to take to avoid spreading the infection from one person to another.

Resources

Periodicals

"Bullous Impetigo." Archives of Pediatrics and Adolescent Medicine 151, no. 11 (November 1997): 1168+.

Key terms

Systemic — Involving the whole body; the opposite of localized.

Ulcer — An irritated pit in the surface of a tissue.

Vesicle — A bump on the skin filled with fluid.

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impetigo /im·pe·ti·go/ (im?pe-ti´go) [L.]

1. impetigo contagiosa; a streptococcal or staphylococcal skin infection marked by vesicles that become pustular, rupture and form yellow crusts.impetig´inous

2. i. bullosa.

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impetigo bullo´sa , bullous impetigo impetigo in which the developing vesicles progress to form large bullae, which collapse and become covered with crusts.

impetigo contagio´sa  impetigo (1).

impetigo herpetifor´mis  a very rare, acute dermatitis with symmetrically ringed, pustular lesions, occurring chiefly in pregnant women and associated with severe constitutional symptoms.

impetigo neonato´rum  impetigo bullosa of newborn infants.

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im·pe·ti·go (mp-tg)

n. pl. im·pe·ti·gos

A contagious skin infection caused by staphylococcal or streptococcal bacteria and characterized by the eruption of superficial pustules that rupture and form thick yellow crusts, usually on the face; it is most commonly seen in children. Also called impetigo contagiosa, impetigo vulgaris.

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impetigo (im´ptī´gō),

n an inflammatory disease of the skin mainly in children; characterized by pustules and yellow-colored crust. Caused by
Streptococcus or
Staphylococcus. Highly contagious.

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impetigo

usually a staphylococcal skin infection marked by vesicles or bullae that become pustular, rupture, and form yellow crusts. In animals a superficial infection of the face of newborn piglets, the abdominal skin of puppies, and one of the teats of cows, go under the name of impetigo. See also udder impetigo, contagious porcine pyoderma.

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impetigo contagiosa

see exudative epidermitis.

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impetigo Dermatology A contagious streptococcal or staphylococcal infection that erodes the skin and dries to form a yellow-crusted sore; impetigo in children is associated with poor hygiene; it may follow RTIs in adults Clinical Pruritus, blisters, oozing, tightly adherent crusting, which tends to spread and form deep ulcers