Monkeypox (Mpox) Clinical Presentation

Updated: Nov 29, 2022
  • Author: Mary Beth Graham, MD, FIDSA, FACP; Chief Editor: William D James, MD  more...
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Presentation

Physical Examination

The most reliable clinical sign differentiating monkeypox (mpox) from smallpox and chickenpox is enlarged lymph nodes, especially the submental, submandibular, cervical, and inguinal nodes. [16] 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.

The 2022 outbreak has produced atypical symptoms when compared to previous monkeypox outbreaks. [8] These symptoms may include:

  • Scant or even single lesions or even the complete absence of skin lesions
  • Lesions mostly confined to the genital and perianal areas, presenting with anal pain and bleeding
  • Lack of prodromal symptoms, such as fever, myalgias, fatigue, and headache before the appearance of a rash

Some patients experience herald cutaneous lesions at the point of sexual contact prior to further symptoms.

Previous outbreaks

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. [33]

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. 

Ocular monkeypox

Ocular monkeypox is a potentially sight-threatening infection and requires urgent assessment and treatment. Signs and symptoms include vision changes, eye pain, itching, redness, swelling, and foreign body sensation. Clinicians should consider prompt initiation of treatment with systemic antiviral therapy, in addition to trifluridine ophthalmic drops in patients with ocular manifestations.