Cellulitis Flashcards
Cellulitis is an acute … infection of the skin.
Cellulitis is an acute bacterial infection of the skin.
Cellulitis refers to an acute bacterial skin infection that affects both the … and … tissue. It may occur anywhere on the body and ranges form a self-limiting infection to severe … infection.
Cellulitis refers to an acute bacterial skin infection that affects both the dermis and subcutaneous tissue. It may occur anywhere on the body and ranges form a self-limiting infection to severe necrotising infection.
Cellulitis is a very common condition. It can occur at any age, but is mostly seen in middle-aged to older adults and usually affects the … limbs.
Cellulitis is a very common condition. It can occur at any age, but is mostly seen in middle-aged to older adults and usually affects the lower limbs.
Cellulitis is commonly caused by both … and … species.
Cellulitis is commonly caused by both Streptococcus and Staphylococcus species.
Cellulitis occurs due to disruption of the skin barrier (e.g. cut, abrasion), which allows entry of microorganisms. Both … and Staphylococcus are common skin commensal organisms that can enter the skin and cause infection.
Cellulitis occurs due to disruption of the skin barrier (e.g. cut, abrasion), which allows entry of microorganisms. Both Streptococcus and Staphylococcus are common skin commensal organisms that can enter the skin and cause infection.
Risk factors for cellulitis: (7)
Trauma Leg ulceration Fungal infection Lymphoedema Venous insufficiency Obesity Pregnancy
… is characterised by the hallmarks of inflammation including pain, swelling, warmth and erythema.
Cellulitis is characterised by the hallmarks of inflammation including pain, swelling, warmth and erythema.
Symptoms of cellulitis (5)
Pain Redness Swelling Fever Malaise
Signs of cellulitis:
Pain on palpation
Erythema
Skin warmth
Superficial bullae or blisters: may be present
Abscess: may complicate cellulitis. Collection of pus within dermis or subcutaneous space. Painful and fluctuant.
Lymphadenopathy
Cellulitis is a clinical diagnosis based on the classic appearance of …, warm and … skin.
Cellulitis is a clinical diagnosis based on the classic appearance of erythematous, warm and oedematous skin.
Are investigations needed for cellulitis?
Laboratory investigations are often unnecessary if the patient is otherwise clinically well. They are more likely to be completed in patients presenting to secondary care (e.g. hospital)
Erysipelas - This describes a form of … that involves the more superficial dermal structures. It is characterised by a raised, well demarcated border and usually occurs secondary to beta-haemolytic streptococcal infection. Treatment is also with antibiotics.
This describes a form of cellulitis that involves the more superficial dermal structures. It is characterised by a raised, well demarcated border and usually occurs secondary to beta-haemolytic streptococcal infection. Treatment is also with antibiotics.
The severity of cellulitis may be assessed using the … classification:
Class I: no signs of systemic toxicity. No uncontrolled co-morbidity (e.g. diabetes mellitus)
Class II: systemically unwell or systemically well but with a comorbidity
Class III: significant systemic upset (e.g. tachycardia, tachypnoea), unstable co-morbidities or limb-threatening infection due to vascular compromise.
Class IV: sepsis or severe life-threatening infection (e.g. development of necrotizing fasciitis)
Differential diagnosis for cellulitis: Several infective and non-infective aetiologies may be confused with cellulitis.
List the infective differentials (5)
Necrotising fasciitis: a severe skin infection that causes progressive destruction of the muscle fascia and overlying subcutaneous fat. It is a surgical emergency requiring urgent debridement.
Toxic shock syndrome: invasive group A streptococcal infection that may cause necrotising soft tissue infection. Due to the release of exotoxins that act as ‘superantigens’ and large release inflammatory cytokines.
Septic arthritis: joint infection. May be difficult to distinguish if cellulitis overlies a joint
Bursitis: inflammation of a bursa (fluid-filled sac). May present alongside cellulitis
Osteomyelitis: may be present with overlying cellulitis.
Differential diagnosis for cellulitis: Several infective and non-infective aetiologies may be confused with cellulitis.
List the non-infective differentials (6)
Deep vein thrombosis: can also cause a painful, swollen, erythematous leg
Contact dermatitis: characteristically pruritic and no systemic signs of infection
Drug reaction: usually distinguished by typical location (trunk, proximal extremities) and erythematous maculopapular rash
Insect bite: may trigger local inflammatory reaction at punctured site. Alternatively, may be delayed skin reaction with features of local swelling, itching and erythema.
Lymphoedema: abnormal accumulation of interstitial fluid
Stasis dermatitis: inflammatory reaction due to chronic venous insufficiency
Bedside investigations for a patient with cellulitis who is systemically unwell, at risk of deterioration, or suspected of having complications
Skin swabs: debrided material, open wound, obvious portal for bacterial entry
Blood glucose: patients with diabetes at increased risk
Bloods for a systemically unwell patient with cellulitis include:
FBC U&E LFT CRP Blood cultures: < 10% of blood cultures are positive in cellulitis HbA1c
Imaging for a systemically unwell patient with cellulitis:
Ultrasound: may be used to look for underlying abscess
X-ray: may be needed to assess for osteomyelitis
Management of cellulitis:
The principle management of cellulitis is with antibiotics
Patients with mild cellulitis (e.g. Eron I and some Eron II) - how are they treated?
Patients with mild cellulitis (e.g. Eron I and some Eron II) may be treated in the community with oral antibiotics. Typical antibiotic choices are penicillin (e.g. phenoxymethylpenicillin) and/or flucloxacillin due to the high rate of streptococcal and staphylococcal infections. Erythromycin/clarithromycin are good alternatives in patients with penicillin allergy (local antibiotics guidelines should always be sought).
What are the typical antibiotic choices for mild cellulitis? (Eron I and some Eron II)
Typical antibiotic choices are penicillin (e.g. phenoxymethylpenicillin) and/or flucloxacillin due to the high rate of streptococcal and staphylococcal infections.
What are the typical antibiotic choices for mild cellulitis in patients with a penicillin allergy? (Eron I and some Eron II)
Erythromycin/clarithromycin are good alternatives in patients with penicillin allergy (local antibiotics guidelines should always be sought).
Some patients with cellulitis may require hospital admission for assessment and intravenous antibiotics. These include patients with:
Eron class III or IV
Severe, rapidly developing cellulitis
High-risk patient: very young (e.g. < 12 months old), frail, immunocompromised
Orbital/facial cellulitis: high risk of complications
Significant lymphedema (unlikely to resolve with oral antibiotics)
Suspected complications: e.g. septic arthritis or osteomyelitis
IV antibiotic options for cellulitis:
Intravenous flucloxacillin, clindamycin and/or vancomycin may be used as intravenous antibiotic choices. Clindamycin is particularly important in patients with suspected group A streptococcal infection as it suppresses bacterial exotoxin production (plus other beneficial effects). Clindamycin may be needed in combination with a beta-lactam antibiotic (e.g. penicillin, cephalosporin, carbapenem).
In patients with severe cellulitis or systemically unwell, advice from microbiology is usually required. It is always recommended to follow local antibiotic guidelines.
