Cellulitis and Erysipelas Flashcards

1
Q

Define cellulitis.

A

Cellulitis is an acute spreading infection of the skin with visually indistinct borders that principally involves the dermis and subcutaneous tissue.

It is characterised by erythema, oedema, warmth, and tenderness, and commonly occurs in an extremity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define erysipelas.

A

Erysipelas is a distinct form of superficial cellulitis with notable lymphatic involvement and is raised, sharply demarcating it from uninvolved skin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How common is cellulitis?

A

0.4% of hospital admissions

some forms of cellulitis are unique to women

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the aetiology of cellulitis?

A

Disruptions in the cutaneous barrier –> entry of micro-organisms to the dermal and subcutaneous tissues

Beta -haemolytic streptococci and staphylococcus aureus are the most common organisms.

MRSA is not uncommon.
If occurring in the orbit, Haemophilus influenzae is the most common cause. The infection
often arises from adjacent sinuses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the risk factors for cellulitis?

A
  • Prior episode of cellulitis - probably due to persistance of other risk factors.
  • Ulcer/wound
  • Dermatosis
  • Tinea pedis interdigitalis - disruption of cutaneous barrier allows micro-organism entry into tissue.
  • Lymphoedema
  • Venous insufficiency/chronic leg oedema - Cellulitis following saphenous venectomy is a well-recognised association. Chronic oedema may also contribute to risk - thought that stasis of fluid reduced local host defences, leading to infection.
  • Overweight -

Other:

  • Bite (human/dog/cat)
  • Fresh water exposure
  • Salt water exposure
  • Diabetic foot ulcer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the signs and symptoms of cellulitis?

A
  • Skin discomfort
  • Macular erythema with indistinct borders on the skin - cellulitis
  • Shiny, smooth skin
  • Not normally itchy
  • Disruption of cutaneous barrier
  • Erysipelas - raised erythema with clearly demarcated margins. Less serious than cellulitis.
  • Possible fever, malaise

Other:

  • Lesion: erythema, oedema, warm tender indistinct margins. Pyrexia may signify systemic spread.
  • Exclude abscess: Test for fluid thrill or fluctuation. Aspirate if pus suspected.
  • Periorbital: Swollen eyelids. Conjunctival injection.
  • Orbital cellulitis: Proptosis, impaired acuity and eye movement. Test for relative afferent pupillary defect, visual acuity and colour vision (to monitor optic nerve function).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the main difference between cellulitis and erysipelas?

A

Erysipelas is more superficial. It may also be well demarcated.

Cellulitis affects deeper tissues.This is a more serious infection. However, it may not always be possible to distinguish between the two .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the most common locations for cellulitis?

A
  • Mostly starts on lower leg around ankle
  • Periorbital cellulitis occurs on around the eyelids
  • Erysipelas is more common on the face than cellulitis
  • Sometimes sinusitis cab spread to the eye causing orbital cellulitis
  • Leaning on the elbow too much can lead to olecranon bursitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What conditions can be mistaken for cellulitis? What differentiates them? (2)

A
  • Insect bites can have surrounding redness which is usually only a histamine reaction and goes away in a few days. Insect bites are itchy but cellulitis isn’t. Cellulitis also takes more time to develop (not overnight).
  • Varicose eczema - redness on legs of elderly; usually occurs on both legs unlike cellulitis. It also isn’t painful unlike cellulitis.

Correct diagnosis is important as it prevents taking antibiotics for no reason.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What investigations should you do for cellulitis?

A

Usually clinical diagnosis - history and examination.

Other:

FBC - raised WCC

Purulent focus culture and molecular diagnostic procedures - growth of typical pathogen (e.g. Staph aureus). Done if cellulitis is associated with a wound or purulent focus.

MRI/CT - in orbital cellulitis to assess posterior spread

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do you treat cellulitis?

A

Medical: Oral penicillins (e.g. flucloxacillin, benzylpenicillin, coamoxiclav) or tetracyclines are
effective in most community-acquired cases. In the hospital, treat empirically using local
microbiological guidelines but change depending on sensitivity of any cultured organisms.
Intravenous use may be necessary.

Surgical: Orbital decompression may be necessary in orbital cellulitis. This is an emergency.

Abscess: Abscesses can be aspirated, incised and drained or excised completely.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the complications of cellulitis?

A
  • Sepsis
  • In orbital cellulitis, there may be permanent vision loss and spread to brain, abscess formation, meningitis, cavernous sinus thrombosis.
  • Damage to lymphatics –> chronic oedema
  • Localised tissue damage
  • Sloughing of overlying skin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the prognosis with cellulitis?

A

Excellent - resolves with therapy

Recurrence may occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the most to least likely diagnosis and why?

(ruptured Baker’s cyst, ischaemic leg, DVT, urticarial reaction, cellulitis)

A
  1. Cellulitis - red, swollen, tender leg and a pyrexia so most likely. Usually well demarcated and warm to palpation
  2. DVT- possible with fever but must ask RFs
  3. Ischaemic leg
  4. Ruptured Bakers cyst - would be very acute onset and at the back of the knee (often associated with OA of the knee joint)
  5. Urticarial reaction - does not present in this manner
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the two most common organisms causing skin and soft tissue infections?

A
  1. Streptococcus pyogenes (also known as Group A Streptococcus)
  2. Staphylococcus aureus.

Other:

  • Strep viridans = oral cavity as commensal
  • Staph epidermidis = coagulase negative staph living on skin as harmless commensal
  • Enterococcus faecalis = gut flora

All can cause disease when in the wrong place or with assistance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the different classes of cellulitis?

A
  1. Class I: Patients lack systemic signs or symptoms.
  2. Class II: Patients have comorbid conditions that affect recovery.
  3. Class III: Patients have accompanying limb threatening conditions or confusion, tachycardia, or other unstable conditions.
  4. Class IV: Patients have severe, life threatening infection or sepsis
17
Q

How does the management differ depending on class of cellulitis?

A

Treatment of cellulitis depends on its classification.

  1. Class I: oral antibiotics in an outpatient setting
  2. Class II: oral or I.V. antibiotics in an outpatient setting
  3. Class III: hospitalization for I.V. antibiotic therapy
  4. Class IV: urgent hospitalization for intensive multiple therapy and specialist consultation