The differential diagnoses include usually smallpox, chickenpox, measles, bacterial skin infections, scabies, medicamentous allergies and syphilis.
If a woman has certain infections during pregnancy, such as rubella or chickenpox, the baby may develop a cataract before birth.
The presence of lymphadenopathy can help identify the disease as monkeypox since it is not characteristic of either smallpox or chickenpox.