Lymphangitis is caused by :
**Core Concept**
Lymphangitis is an inflammatory condition of the lymphatic vessels, characterized by the spread of infection from a primary site to the lymphatic system. This condition is often associated with bacterial infections, particularly those caused by Staphylococcus aureus or Streptococcus species.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of lymphangitis, which involves the spread of infection from a primary site to the lymphatic vessels. This is typically caused by bacterial infections, such as those caused by Staphylococcus aureus or Streptococcus species, which produce exotoxins that damage the lymphatic vessels and lead to inflammation. The lymphatic system's inability to effectively clear the infection due to the damage to its vessels contributes to the development of lymphangitis.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because lymphangitis is not primarily caused by viral infections. While some viral infections can cause lymphadenitis (inflammation of the lymph nodes), they are not typically associated with lymphangitis.
* **Option B:** This option is incorrect because lymphangitis is not primarily caused by fungal infections. Fungal infections can cause a range of lymphatic system disorders, but they are not typically associated with lymphangitis.
* **Option C:** This option is incorrect because lymphangitis is not primarily caused by parasitic infections. While some parasitic infections can cause lymphatic system disorders, they are not typically associated with lymphangitis.
**Clinical Pearl / High-Yield Fact**
Lymphangitis is often associated with a streak of redness and tenderness along the affected lymphatic vessel, which can be a valuable clinical sign for diagnosing this condition.
**Correct Answer: A. Bacterial infections.**