Some cases from the 2022 outbreak seem to lack or have mild prodromal symptoms. Look for one or a few papular, vesicular, pustular, or ulcerative lesions involving the genitals or perianal region. Some patients may present with proctitis or pharyngitis. Individuals with advanced or inadequately treated HIV are at risk of life-threatening disease.
In a case series of over 500 patients with MPX infection diagnosed between April 27 and June 24, 2022, at over 40 locations and 16 countries, the most common body locations for lesions were the anogenital area (73%); the trunk, arms, and legs (55%); the face (25%); and the palms and soles (10%). Lesion types included macules, pustules, vesicles, and crusted lesions. Lesions in different stages of development were seen. Mucosal lesions were present in around 40% of patients. Systemic manifestations included fever, lethargy, myalgia, headache, and lymphadenopathy; these symptoms often preceded a generalized rash.
Impact of skin color on clinical presentation: In darker skin colors, erythema can be difficult to discern, and may appear pink, violaceous, dark brown, or any shade of gray. In lighter skin colors, they may appear any shade of pink or red.
Immunocompromised patient considerations: Per the CDC, severe manifestations have included the following.
- Atypical or persistent rash with coalescing or necrotic lesions, or both, some which have required extensive surgical debridement or amputation of an affected extremity.
- Lesions on a significant proportion of the total body surface area, which may be associated with edema and secondary bacterial or fungal infections, among other complications.
- Lesions in sensitive areas (including mucosal surfaces such as, oropharynx, urethra, rectum, vagina) resulting in severe pain that interferes with activities of daily living.
- Bowel lesions that are exudative or cause significant tissue edema, leading to obstruction.
- Severe lymphadenopathy that can be necrotizing or obstructing (such as in airways).
- Lesions leading to stricture and scar formation resulting in significant morbidity such as urethral and bowel strictures, phimosis, and facial scarring.
- Involvement of multiple organ systems and associated comorbidities, including:
- Oropharyngeal lesions inhibiting oral intake
- Pulmonary involvement with nodular lesions
- Neurologic conditions including encephalitis and transverse myelitis
- Cardiac complications including myocarditis and pericardial disease
- Ocular conditions including severe conjunctivitis and sight-threatening corneal ulcerations
- Urologic involvement including urethritis and penile necrosis
In classic MPX (that is commonly seen in Africa), skin lesions develop 1-3 days after onset of fever. Skin lesions evolve from macules (that are present for 1-2 days) to papules (1-2 days), then to vesicles (1-2 days) and pustules (that last for 5-7 days) and, ultimately, crusts (that may last for up to 14 days). Umbilication of vesicles and pustules may be seen. Crusts may be hemorrhagic. While the majority of lesions are at the same stage of development, lesions at differing stages may be seen.
In classic MPX, the rash usually starts on the face and distal extremities with centripetal spread to involve the more proximal extremities and trunk. Lesions commonly involve the face (95%), palms and soles (75%), and oral mucous membranes (70%) and, less commonly, the genitalia (30%; although among 2022 cases this seems higher) and conjunctiva (20%; can be sight-threatening). Lesion number can vary from 1 to more than 1000. In addition to lesions on the head, trunk, and extremities, patients can have initial and satellite lesions on the palms, soles, and extremities. Rashes can generalize in some patients.
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