Key Characteristics for Identifying Mpox
- Lesions are firm or rubbery, well-circumscribed, deep-seated, and often develop umbilication (resembles a dot on the top of the lesion).
- During the current global outbreak:
- Lesions often occur in the genital and anorectal areas or in the mouth.
- Rash is not always disseminated across many sites on the body.
- Rash may be confined to only a few lesions or only a single lesion.
- Rash does not always appear on palms and soles.
- Rectal symptoms (e.g., purulent or bloody stools, rectal pain, or rectal bleeding) have been frequently reported in the current outbreak.
- Lesions are often described as painful until the healing phase when they become itchy (crusts).
- Fever and other prodromal symptoms (e.g., chills, lymphadenopathy, malaise, myalgias, or headache) can occur before rash but may occur after rash or not be present at all.
- Respiratory symptoms (e.g. sore throat, nasal congestion, or cough) can occur.
Lesions typically develop simultaneously and evolve together on any given part of the body. The evolution of lesions progresses through four stages—macular, papular, vesicular, to pustular—before scabbing over and desquamation.
The incubation period is 3-17 days. During this time, a person does not have symptoms and may feel fine.
The illness typically lasts 2-4 weeks.
The severity of illness can depend upon the initial health of the individual and the route of exposure. The West African virus genetic group, or clade, which is the clade involved in the current outbreak, is associated with milder disease and fewer deaths than the Congo Basin virus clade.
Mpox Disease Stages
- Mpox disease is characterized by an incubation period, prodrome, and rash.
- Incubation Period: Infection with mpox virus begins with an incubation period where the person does not have symptoms and may feel fine. The incubation period is roughly 1-2 weeks. A person is not contagious during this period. Physicians are currently recommended to monitor patients up to 21 days.
- Prodrome: People with mpox infection may develop an early set of symptoms (prodrome). These symptoms may include fever, malaise, headache, sore throat, or cough, and (in many cases) swollen lymph nodes. Lymphadenopathy is a characteristic feature of mpox, and lymph nodes may swell in the neck (submandibular & cervical), armpits (axillary), or groin (inguinal) and can occur on both sides of the body or just one. A person may be contagious during this period. Instruct patients to isolate if they develop symptoms.
- Rash: In some recent mpox cases, people have presented with a rash without a recognized prodrome. Many of the recent cases have only had localized lesions and have not presented with diffuse rash often seen in figures. People with mpox infection develop lesions that typically progress from papules, macules, vesicles, pustules, and then scabs. A person is contagious until after all the scabs on the skin have fallen off and a fresh layer of intact skin has formed underneath. Decisions regarding discontinuation of isolation precautions at a healthcare facility and at home should be made in consultation with the local or state health department.
*This is a typical timeline, but timeline can vary.
Pitted scars and/or areas of lighter or darker skin may remain after scabs have fallen off. Once all scabs have fallen off and a fresh layer of skin has formed, a person is no longer contagious.