Final answer:
The condition described is most consistent with meningococcemia, a severe infection caused by Neisseria meningitidis, leading to high fever, rash, and changes in consciousness, with rifampin prophylaxis for close contacts.
Step-by-step explanation:
Based on the symptoms provided - purple-colored to dark-red painful skin lesions all over body, acute-onset high fever, headache, level of consciousness changes, and rifampin prophylaxis for close contacts - the correct answer appears to be c. Meningococcemia.
Meningococcemia is a severe bacterial infection caused by Neisseria meningitidis. It enters the bloodstream and multiplies, leading to symptoms such as high fever, headache, and a rash that can progress to purpuric lesions. It is a life-threatening condition that can cause changes in the level of consciousness and, if not treated promptly, can lead to shock and death. Rifampin is commonly used as a prophylactic treatment for close contacts of someone with meningococcal infection to prevent spread of the disease.
Other referenced conditions do not match the specific combination of symptoms and preventive measures described for the contacts, making meningococcemia the most fitting diagnosis.