While chickenpox and mpox share some symptomatic similarities, it’s critical for emergency room physicians to quickly differentiate between the two to ensure proper patient care and public health safety. Here’s a breakdown of the key distinctions, focusing on the practical aspects:

Incubation Period:

• Mpox: 5-21 days (most cases present after 7-14 days)
• Chickenpox: 4-7 days

Lymph Node Swelling:

• Mpox: Swollen lymph nodes are a common symptom.
• Chickenpox: Lymph node swelling is not typically present.

Lesion Characteristics:

• Mpox: Deep-seated, firm, rubbery lesions that may umbilicate (form a central depression).
• Chickenpox: Thin-walled, fragile lesions that break easily.

Transmission:

• Mpox: Spreads through direct contact with infectious sores, scabs, body fluids, or prolonged face-to-face contact.
• Chickenpox: Highly contagious and spreads easily through the air by coughing or sneezing.

Demographics:

• Mpox: Currently primarily affecting men who have sex with men.
• Chickenpox: Most common in children but can affect unvaccinated adults.

Severity:

• Mpox: Can be more severe, with a higher risk of complications and even fatality, particularly in immunocompromised individuals.
• Chickenpox: Generally mild, but can be severe in some cases.

ER Approach:

• Suspect Mpox? Isolate First: Initiate isolation precautions immediately if mpox is suspected.
• Detailed History & Exam: Elicit a thorough history, including travel, potential exposures, and sexual history. Examine the rash meticulously, noting its distribution and any lymph node swelling.
• Testing is Essential: If mpox is a possibility, collect lesion swabs for PCR testing.
• Supportive Care & Antivirals: Provide supportive care for both diseases. Consider antivirals (e.g., tecovirimat) for severe mpox or high-risk patients.
• Public Health Notification: Report suspected or confirmed mpox cases to public health authorities.

Recognizing these key differences between chickenpox and mpox will empower ER physicians to make swift, informed decisions, leading to improved patient outcomes and effective public health responses.

Additional Considerations for ER Physicians

• Mortality Rate: While generally lower than historical rates, mpox can still be fatal, especially in vulnerable populations. Be vigilant for complications and escalate care as needed.
• Direct Viral Invasion: In severe cases, the mpox virus can directly invade organs, leading to serious complications. Prompt diagnosis and treatment are critical.
• Treatment Options: Supportive care is crucial, but tecovirimat is the preferred antiviral for severe mpox or high-risk patients.

By prioritizing rapid assessment, isolation, and appropriate management, ER physicians play a pivotal role in mitigating the impact of both chickenpox and mpox.