Mpox (formerly called monkeypox) typically causes a skin rash along with flu-like symptoms such as fever, headache, muscle aches, back pain, low energy, sore throat, and swollen lymph nodes. Symptoms usually begin within a week of exposure but can appear anywhere from 1 to 21 days after contact with the virus. The full illness, from the first symptom to the last scab falling off, generally lasts 2 to 4 weeks.
Early Symptoms Before the Rash
For many people, mpox starts with a set of general symptoms that feel a lot like the flu: fever, headache, muscle aches, back pain, sore throat, and deep fatigue. Swollen lymph nodes are also common early on, particularly in the jaw, neck, or groin area. That lymph node swelling is one of the key features that sets mpox apart from chickenpox and other rash-causing illnesses, which typically don’t cause noticeable swelling in those areas.
Not everyone follows this pattern, though. Some people develop a rash as their very first symptom, with little or no fever beforehand. Others get a sore throat or body aches days before any skin changes appear. The order and intensity of symptoms can vary quite a bit from person to person.
How the Rash Develops and Changes
The rash is the hallmark of mpox, and it moves through a predictable series of stages over roughly two to three weeks. Lesions sometimes appear first inside the mouth or on the tongue before showing up on the skin.
- Flat spots (macules): The rash begins as flat, discolored patches on the skin. This stage lasts about 1 to 2 days.
- Raised bumps (papules): Those flat spots become raised, firm bumps over the next 1 to 2 days.
- Fluid-filled blisters (vesicles): The bumps fill with clear fluid, lasting another 1 to 2 days.
- Pus-filled blisters (pustules): The fluid turns opaque and yellowish. These lesions feel firm and deep-seated, often developing a visible dent in the center. This stage lasts about 5 to 7 days before the lesions begin to crust over.
- Scabs: By the end of the second week, the pustules have dried into scabs. The scabs remain for roughly another week before falling off on their own.
A person remains contagious until all scabs have separated and fresh skin has formed underneath. The total rash timeline varies, but the progression from flat spots to scabs typically takes about two to four weeks.
Genital, Rectal, and Oral Lesions
In the ongoing outbreak, more than 40% of patients have developed lesions on mucosal surfaces, particularly around the genitals, anus, and inside the mouth or throat. These lesions can cause pain that feels disproportionately severe compared to how they look. A small cluster of sores in the genital or anal area can be intensely painful even when the lesions appear minor on the surface.
Rectal pain and inflammation of the rectum (proctitis) are frequently reported. Symptoms can include pain during bowel movements, a persistent feeling of needing to go, and rectal bleeding. In rare cases, complications have included rectal perforation or abscess formation.
Genital lesions can cause swelling of the penis or foreskin, difficulty urinating, or blood in the urine if the urethra is involved. Secondary bacterial infections of genital skin have also been reported. While data on female patients is more limited, lesions can similarly affect the vulva and surrounding tissue, with risks of pain, scarring, and urethral complications.
Eye Involvement
Mpox can occasionally affect the eyes, and this is one of the more serious complications. Warning signs include eye pain, increasing redness, and changes in vision. If the virus reaches the cornea, it can cause ulcers that may scar and lead to permanent vision loss. Bacterial infections can develop on top of corneal damage, making the situation worse. Any eye symptoms during an mpox infection warrant urgent evaluation by an eye specialist.
How Severity Differs Between Variants
Two main viral clades are circulating globally. Clade II, which drove the large 2022 international outbreak, has a mortality rate below 0.1%, and transmission has been almost exclusively linked to sexual contact. Clade I, found primarily in Central Africa, historically carried a higher fatality rate, though recent data puts it at 2.5% or lower when people receive good supportive care. Clade I also spreads more readily through household contact and in healthcare settings. The symptoms themselves are similar for both variants, and both are treated and prevented in the same ways. Most deaths from either clade occur in people with weakened immune systems, including young children with malnutrition.
Getting Tested
Testing for mpox involves swabbing the surface of skin lesions. The swab is sent for a PCR test that detects the virus’s genetic material. If you have lesions in different stages or in different body locations, samples are typically collected from more than one spot to improve accuracy. The type of swab used may vary depending on whether your lesions are still fluid-filled or have already started crusting. You should not break open or puncture lesions yourself before testing.
Testing is most reliable once a visible rash has developed. If you have only flu-like symptoms and no lesions yet, a healthcare provider may ask you to return for testing once skin changes appear.