True/False statements regarding cellulitis are: 1. Caused by streptococcus pyogenes 2. Causes SIRS 3. Localised infection 4. Abscess if any should be drained 5. I & D should not be done
**Cellulitis Core Concept**
Cellulitis is a bacterial skin and soft tissue infection characterized by diffuse inflammation of the dermis and subcutaneous tissue, often caused by streptococci and staphylococci. It typically presents with erythema, edema, warmth, and tenderness.
**Why the Correct Answer is Right**
Option 1: **True**. Streptococcus pyogenes is a common cause of cellulitis, particularly in children and young adults. It produces toxins that lead to localized tissue damage and inflammation. Option 2: **True**. Cellulitis can cause Systemic Inflammatory Response Syndrome (SIRS) due to the release of pro-inflammatory cytokines and mediators. Option 3: **False**. Cellulitis is a diffuse infection that can spread rapidly, so it's not localized. Option 4: **True**. Abscesses should be drained as they can be a complication of cellulitis. Option 5: **False**. Incision and drainage (I&D) may be necessary for certain cases of cellulitis, such as abscesses or necrotic tissue.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because cellulitis is not always caused by streptococcus pyogenes (it can also be caused by staphylococci and other bacteria).
**Option B:** Incorrect because cellulitis is not a localized infection (it can spread rapidly).
**Option C:** Incorrect because I&D may be necessary for certain cases of cellulitis.
**Option D:** Incorrect because I&D should be done when necessary to prevent complications.
**Clinical Pearl / High-Yield Fact**
Cellulitis can mimic other skin conditions such as erysipelas, which is a well-demarcated, raised, and painful infection typically caused by group A beta-hemolytic streptococci. Remember to always consider the patient's clinical presentation, laboratory results, and imaging studies to make an accurate diagnosis.
**Correct Answer: B. All of the above statements are true.**