**Question:** Following are true of erysipelas except a) Streptococcal infection b) Contagious and infectious c) Margins are raised d) Common in tropics

**Core Concept:** Erysipelas is a type of skin infection caused by Streptococcus bacteria, specifically Streptococcus pyogenes or Streptococcus beta-hemolyticus. It is not contagious or infectious, meaning it does not spread easily from person to person. The infection typically presents with raised margins on the skin, which sets it apart from other skin diseases. Erysipelas is not commonly seen in tropical regions due to a lower prevalence of the causative bacteria in those areas, making option D incorrect.

**Why the Correct Answer is Right:** Erysipelas is caused by Streptococcus bacteria, which are not contagious. This is because the bacteria are not easily transmitted between individuals. Additionally, erysipelas presents with raised margins on the skin, which distinguishes it from other skin diseases. Lastly, the infection is not commonly seen in tropical regions due to the lower prevalence of Streptococcus bacteria in these areas.

**Why Each Wrong Option is Incorrect:**

A) Streptococcal infection: Although erysipelas is caused by Streptococcus bacteria, it is not a general term for all streptococcal infections. Streptococcal infections can be contagious, whereas erysipelas is not.

B) Contagious and infectious: As mentioned earlier, erysipelas is not contagious due to the specific type of Streptococcus bacteria involved. The infection is not easily transmitted between individuals.

C) Margins are normal: Erysipelas presents with raised margins on the skin, which is a key feature differentiating it from other skin diseases. Therefore, this option is incorrect.

D) Common in tropics: Erysipelas is not commonly seen in tropical regions due to the lower prevalence of Streptococcus bacteria in these areas. The infection is more prevalent in temperate climates, making this option incorrect.

**Clinical Pearl:** Erysipelas is characterized by its distinct clinical presentation, including raised margins on the skin. Understanding the underlying causative agent and the differences between erysipelas and other skin conditions is essential for accurate diagnosis and treatment. In tropical regions, the infection might be less common due to the lower prevalence of Streptococcus bacteria.