Cellulitis is a bacterial infection of the deep dermis and subcutaneous tissue. It is most commonly caused by S. pyogenes and S. aureus.5 Bacteria may gain access to the dermis via a break in the skin barrier in healthy adults, whereas the hematogenous route is more common in immunocompromised patients. The affected skin is usually erythematous, swollen, painful, and warm to the touch. Severe cellulitis can be complicated by bullae, pustules, or necrotic tissue. Damage to lymphatic vessels can lead to recurrent episodes of cellulitis.6 In areas of the world endemic for lymphatic filariasis, it is important to rule out this disease in cases of recurrent bouts of lower-extremity cellulitis and lymphangitis.

1. CELLULITIS
PRESENTED BY
R.PRIYA

2. INTRODUCTION
Skin is the largest organ of human body. Skin is first line of defence system of
human body. It forms a barrier and protects internal organs from external foreign
bodies including bacteria, viruses, fungi etc.
Skin has three layers- Dermis, Epidermis and Hypodermis. The tissue beneath the
skin is called Subcutaneous tissue. This consists of fats and collagen which
regulate body temperature and protect the body. Normally there are many types of
bacteria on skin which may enter our body through cracks, breaks, cuts, injuries,
ulcers etc. They can then multiply and spread to cause infection of skin called
Ceulitis.

3. DEFINITION
Cellulitis is a bacterial infection involving the inner layers of the skin.[1] It
specifically affects the dermis and subcutaneous fat
Cellulitis may spread rapidly. Affected skin appears swollen and red and may be
hot and tender.
Without treatment with an antibiotic, cellulitis can be life-threatening.
Cellulitis usually affects the skin on the lower legs, but it can occur in the
face, arms and other areas. It occurs when a crack or break in your skin
allows bacteria to enter.

4. TYPES
Typical presentation of all skin infections
•Soft tissue redness
•Warmth and swelling
•Pain/tenderness
Mild Cellulitis
•Features above
•No systemic features
•No significant co-morbidities
Moderate Cellulitis
•Features above with moderate swelling and tenderness
•Systemic features (eg fever, tachycardia)
Severe Cellulitis
•Features above with severe swelling or tenderness
•Large body surface area involved (eg larger than the patient’s handprint)
•Marked systemic features (eg fever or hypothermia, tachycardia, tachypnoea, altered conscious state, unwell appearance,
hypotension — this is a late sign). See Sepsis
Features suggestive of necrotising fasciitis include:
•severe pain out of keeping with apparent severity of infection
•rapid progression
•marked systemic features (eg high fever with rigors, tachycardia, tachypnoea, hypotension, confusion, vomiting). See Sepsis

5. CAUSES
Cellulitis is caused by bacteria that enter and infect the tissue through breaks in the
skin. GroupA Streptococcus and Staphylococcus are the most common causes of
the infection and may be found on the skin as normal flora in healthy individuals.
Insect or spider bite, blistering, an animal bite, tattoos, pruritic (itchy) skin rash,
recent surgery, athlete's foot, dry skin, eczema, injecting drugs (especially
subcutaneous or intramuscular injection or where an attempted intravenous injection
"misses" or blows the vein),

6. RISK FACTOR
•The most common causes are Group A streptococcus (GAS) and Staphylococcus aureus.
Impetigo (commonly called "school sores")
•Highly contagious infection of the epidermis, particularly common in young children
Causative organisms are GAS and S. aureus
•May be associated with scabies
Staphylococcal scalded skin syndrome (SSSS)
•Blistering skin disorder induced by the exfoliative (epidermolytic) toxins of S. aureus.
Primarily affects neonates and young children
Necrotising fasciitis
•Rapidly progressive soft tissue infection characterised by necrosis of subcutaneous tissue
•Causative organisms include GAS, S. aureus, anaerobes and is often polymicrobial
•It causes severe illness with a high mortality rate (~25%)
•Recent infection with varicella is a risk factor

7. RISK FACTOR
•Injury. Any cut, fracture, burn or scrape gives bacteria an entry point.
•Weakened immune system. Conditions that weaken your immune system — such as
diabetes, leukemia and HIV/AIDS — leave you more susceptible to infections. Certain
medications also can weaken your immune system.
•Skin conditions. Conditions such as eczema, athlete's foot and shingles can cause
breaks in the skin, which give bacteria an entry point.
•Chronic swelling of your arms or legs (lymphedema). This condition sometimes
follows surgery.
•History of cellulitis. Having had cellulitis before makes you prone to develop it again.
•Obesity. Being overweight or obese increases your risk of developing cellulitis.
• suffered poliomyelitis
• Chickenpox and shingles often result in blisters that break open, providing a gap in the
skin through which bacteria can enter.
• Lymphedema, which causes swelling on the arms and/or legs, can also put an
individual at risk.
• Predisposing factors include skin abrasions, lacerations, burns, eczematous skin, chickenpox,
etc. although the portal of entry of organisms is often not seen

8. PATHOPHYSIOLOGY

9. SIGNS AND SYMPTOMS
•Red area of skin that tends to expand
•Swelling
•Tenderness
•Pain
•Warmth
•Fever
•Red spots
•Blisters
•Skin dimpling

10. DIAGNOSTIC EVAUATION
History
Physical examination
use of bedside ultrasonography
blood cultures are positive in fewer than 5% of all cases
•Swab for Gram stain (charcoal / gel / bacterial transport swab and slide)
and culture if discharge present
•Blood culture is not useful in mild/moderate cellulitis
•Consider imaging (eg ultrasound) if abscess, deep infection or foreign
body suspected

11. MANAGEMENT
•Covering your wound. Properly covering the affected skin will help it
heal and prevent irritation. Follow your doctor’s instructions for dressing
your wound and be sure to change your bandage regularly.
•Keeping the area clean. Follow your doctor’s recommendations for
cleaning the affected skin.
•Elevating the affected area. If your leg is affected, lie down and elevate
your leg above your heart. This will help reduce swelling and ease your
pain.
•Applying a cool compress. If the affected skin is hot and painful, apply
a clean washcloth soaked in cool water. Avoid chemical icepacks, as
these can further irritate damaged skin.

12. MANAGEMENT

13. COMPLICATION
Recurrent episodes of cellulitis may damage the lymphatic drainage system
and cause chronic swelling of the affected limb.
Rarely, the infection can spread to the deep layer of tissue called the fascial
lining. Necrotizing fasciitis is an example of a deep-layer infection. It's an
extreme emergency.

14. PREVENTION
•Wash your wound daily with soap and water. Do this gently as part of your normal bathing.
•Apply a protective cream or ointment. For most surface wounds, an over-the-counter
ointment (Vaseline, Polysporin, others) provides adequate protection.
•Cover your wound with a bandage. Change bandages at least daily.
•Watch for signs of infection. Redness, pain and drainage all signal possible infection and
the need for medical evaluation.
People with diabetes and those with poor circulation need to take extra precautions to prevent
skin injury. Good skin care measures include the following:
•Inspect your feet daily. Regularly check your feet for signs of injury so you can catch
infections early.
•Moisturize your skin regularly. Lubricating your skin helps prevent cracking and peeling. Do
not apply moisturizer to open sores.
•Trim your fingernails and toenails carefully. Take care not to injure the surrounding skin.
•Protect your hands and feet. Wear appropriate footwear and gloves.
•Promptly treat infections on the skin's surface (superficial), such as athlete's
foot. Superficial skin infections can easily spread from person to person. Don't wait to start
treatment.