Monkeypox Clinical Presentation

Updated: Jul 01, 2022
  • Author: Mary Beth Graham, MD; Chief Editor: William D James, MD  more...
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Physical Examination

The most reliable clinical sign differentiating monkeypox from smallpox and chickenpox is enlarged lymph nodes, especially the submental, submandibular, cervical, and inguinal nodes. [11] Note the image below.

Lymphadenopathy in monkeypox. Large nodes in the m Lymphadenopathy in monkeypox. Large nodes in the mandibular, cervical, or inguinal region are commonly seen in monkeypox. The presence of significant lymphadenopathy helps differentiate monkeypox from smallpox and chickenpox.

With regard to enanthema, nonspecific lesions and inflammation of the pharyngeal, conjunctival, and genital mucosae have been observed.

In the exanthema stage, within a particular body region, lesions evolve synchronously over 14-21 days, similar to the development of lesions with smallpox. However, unlike smallpox, skin lesions may appear in crops. In contrast to smallpox, the lesions do not have a strong centrifugal distribution. Lesions progress from macules to papules to vesicles and pustules; umbilication, crusting, and desquamation follow. Most lesions are 3-15 mm in diameter.

Note the image below.

Umbilicated papule on the lower part of the leg. T Umbilicated papule on the lower part of the leg. This smaller lesion still shows the typical umbilicated morphology.

The face, the trunk, the extremities, and the scalp are involved. Lesions appear in covered and uncovered areas. Lesions may be seen on the palms and the soles. Necrosis, petechiae, and ulceration may be features. Pain is unusual, and, if it occurs, it is often associated with secondary bacterial infection. Pruritus may occur.

In patients who have been previously vaccinated against smallpox, a milder form of disease occurs. In children, the lesions may appear as nonspecific, erythematous papules that are 1-5 mm in diameter and suggestive of arthropod bite reactions. Subtle umbilication may be seen.

In the African outbreaks, 20% of unvaccinated patients developed a confluent, erythematous eruption on the face and the upper part of the trunk, which some authors have termed the septicemic rash of monkeypox. [26]

Hemorrhagic and flat forms, which can be seen with smallpox, have not been reported in patients with monkeypox. Deep pock scars can result as the lesions resolve.

During the 2022 outbreak, a significant number of patients with monkeypox are men who have sex with men. In several case, the perianal and genital areas have been reported as the first sites of lesion appearance. Clinicians should have a high suspicion for monkeypox with the identification of characteristic lesions in these areas, particularly if the patient has a history of recent travel. [9]