Skin diseases

المرحلة الرابعة

اعداد

وفاء محمود جاسم. د

Main Subjects 1- What is the common skin diseases?

2- What is impetigo ?

3- What are the main characteristic features of

cellulitis ?

4-What is erysipelas?

Conmen skin diseases

there are three common types of skin

infections: cellulitis, erysipelas, and

impetigo (pyoderma).

Humans are natural hosts for many bacterial

species that colonize the skin as normal

flora.

Staphylococcus aureus and Streptococcus

pyogenes are infrequent resident flora, but

they account for a wide variety of bacterial

pyodermas.

Predisposing factors to infection include

minor trauma, preexisting skin disease,

poor hygiene, and, rarely, impaired host

immunity.

Impetigo Impetigo is a superficial skin infection usually

caused by S. aureus and occasionally by

S. pyogenes.

Prevalence and Risk Factors

Impetigo affects approximately 1% of children.

Pathophysiology and Natural History

S. aureus produces a number of cellular and extracellular products, including exotoxins and coagulase, that contribute to the pathogenicity of impetigo, especially when coupled with preexisting tissue injury. Impetigo commonly occurs on the face (especially around the nares) or extremities after trauma.

Signs and symptoms

Two clinical types of impetigo exist: nonbullous

and bullous. The nonbullous type is more

common and typically occurs on the face and

extremities, initially with vesicles or pustules on

reddened skin. The vesicles or pustules

eventually rupture to leave the characteristic

honey-colored (yellow-brown) crust

Bullous impetigo, almost exclusively caused by

S. aureus, exhibits flaccid bullae with clear yellow

fluid that rupture and leave a golden-yellow

crust.

Diagnosis

Diagnosis is by clinical presentation and

confirmation by culture.

Treatment

For most patients with impetigo, topical

treatment is adequate, either with

bacitracin (Polysporin) or mupirocin

(Bactroban), applied twice daily for 7 to 10

days. Systemic therapy may be necessary

for patients with extensive disease

Cellulitis

Cellulitis is a painful, erythematous infection

of the dermis and subcutaneous tissues

that is characterized by warmth, edema,

and advancing borders

Cellulitis commonly occurs near breaks in

the skin, such as surgical wounds,

trauma, tinea infections , or ulcerations,

but occasionally presents in skin that

appears normal.

Cellulitis

Patients may have a fever and an elevated

white blood cell count.

Cellulitis can occur on any part of the body.

Among the patients in the cohort above, the

most common sites of cellulitis were the

legs and digits, followed by the face, feet,

hands, neck, and buttocks

Cellulitis Symptoms

Cellulitis usually begins as a small area of pain and redness on the skin.

This area spreads to surrounding tissues, resulting in the typical signs of inflammation -- redness, swelling, warmth, and pain. A person with cellulitis can also develop fever and/or swollen lymph nodes in the area of the infection.

• Cellulitis is not contagious because the

top layer (epidermis) of the skin is not

involved and provides a protective cover

over the infected area.

How is cellulitis treated?

• Antibiotics are essential for the treatment

of cellulitis. Penicillin derivatives are

often prescribed to treat cellulitis

• In more advanced cases of cellulitis,

hospitalization and administration of

intravenous antibiotics may be required.

Prevention

Cellulitis may be prevented by :

A/wearing appropriate protective equipment

During work

B/ avoid skin injury, cleaning cuts and skin injuries

with antiseptic soap, keeping wounds clean

and protected

C/watching wounds for signs of

infection, taking the entire prescribed

dose of antibiotic

D/ maintaining good general

health.

Erysipelas Erysipelas is a bacterial infection in the

upper layer of the skin.

It is similar to another skin disorder known

as cellulitis

Erysipelas occurs most frequently in the legs

but also commonly affects the face

Erysipelas "red skin"; also known as "ignis sacer", "holy

fire"

Erysipelas typically characterized with a skin rash, usually on any of the legs and toes, face, arms, and fingers. It is an infection of the upper dermis and superficiallymphatics, usually caused by beta-hemolytic group A Streptococcus bacteria on scratches or otherwise infected areas

Erysipelas is more superficial than cellulitis, and is typically more raised and demarcated

Causes of Erysipelas

• Erysipelas is caused by bacteria penetrating

the outer barrier of the skin. The bacteria

that most commonly cause erysipelas are

known as streptococci

Causes of Erysipelas • cuts and ulcers in the skin

• surgical incisions

• insect bites

• athlete’s foot

• skin conditions such as eczema and psoriasis

• obesity

• swollen legs due to health problems such as heart failure

• uncontrolled diabetes

• injecting illegal drugs

• anything that suppresses the immune system

• having had a previous episode of erysipelas

Risk factors The disease is most common among the

elderly, infants, and children. People

with immune deficiency, diabetes, alcoholism,

skin ulceration, fungal infections, and

impaired lymphatic drainage (e.g.,

after mastectomy, pelvic surgery, bypass grafting)

are also at increased risk in :

1- Sever trauma

2- Previous history of skin infection

3- History of drug intake ( steroid therapy )

Treatment Depending on the severity, treatment

involves either oral or intravenous antibiotics, using penicillins, clindamycin, or erythromycin. While illness symptoms resolve in a day or two, the skin may take weeks to return to normal.

• Because of the risk of re infection, prophylactic antibiotics are sometimes used after resolution of the initial condition. However, this approach does not always stop re infection

Prognosis The disease prognosis includes:

1- Spread of infection to other areas of body can occur through the bloodstream (bacteremia), including septic arthritis.Glomerulonephritis can follow an episode of streptococcal erysipelas or other skin infection, but not rheumatic fever.

2- Recurrence of infection: Erysipelas can recur in 18–30% of cases even after antibiotic treatment.

3- Lymphatic damage

Necrotizing fasciitis, commonly known as "flesh-eating" bacterial infection, is a potentially deadly exacerbation of the infection if it spreads to deeper tissue.