Distinguishing infectious causes of vesicular lesions
| Characteristic | Monkeypox | Chickenpox and herpes zoster | HSV-1 and HSV-2 | Syphilis | Hand, foot and mouth disease | Molluscum contagiosum |
|---|---|---|---|---|---|---|
| Infectious cause | Monkeypox virus | Varicella zoster virus | Herpes simplex virus | Treponema pallidum | Coxsackievirus A and several other enterovirus serotypes | Poxvirus (molluscum contagiosum virus) |
| Subclinical shedding | No* | Yes | Yes | No | Yes | No |
| Incubation period, d | 5–21 | 10–21 | 2–12 | 3–90 | 3–5 | 14–180 |
| Systemic symptoms | Possible prodrome of fever, malaise, myalgias, headache. | Primary: a prodrome of fever, malaise, pharyngitis, anorexia. Reactivation: minority have fever, malaise, headache. | Primary: fever, malaise, myalgias, headache, tender lymphadenopathy. Reactivation: prodromal tingling or shooting pains. | Uncommon | Prodrome is uncommon | None |
| Lymphadenopathy | Tender, regional | Primary: generalized. Reactivation: regional. | Tender, regional | Primary: painless, regional. Secondary: generalized. | Cervical | No |
| Rash | Macules to papules to vesicles to pustules that umbilicate, ulcerate, crust and desquamate. Local pain and pruritis until crusting. Lesion pleomorphism. | Primary: maculopapular, vesicles, scabs appearing in crops. Lesions in all stages. Pruritic. Reactivation: erythematous papules to pustules. Can be hemorrhagic. Crust by 7–10 days. | A cluster of 2–4 mm vesicles on an erythematous base. May progress to vesicopustules and ulcers. Local pain and pruritis. | Primary: chancre. Secondary: maculopapular, may coalesce. Superficial mucosal erosions. Pustules. Condyloma lata. Rarely vesicular. | Oral: 1–5-mm erythematous vesiculoulcerative stomatitis Exanthem: macular, maculopapular, or 1–10-mm vesicular on palms, soles, legs, and arms. Lesions may be at different stages of development. Local pruritis. | 2–5-mm firm, dome-shaped flesh-coloured papules with umbilication. Rarely painful. |
| Location | Primary: site of inoculation. Secondary: spreads to extremities.* Can involve palms and soles. | Primary: head, scalp, trunk, extremities. Reactivation: dermatomal. | Orofacial, genitalia, rectum, hands, eyes | Primary: site of inoculation. Secondary: most commonly on palms and soles, trunk and extremities, intertriginous and mucosal areas. | Oral, palms, soles, arm, legs, buttocks | Anywhere on body, but uncommon in mouth or on palms and soles |
| Diagnosis | Viral PCR of unroofed lesion (dry flocked swab), throat or nasopharyngeal swab, serum sample or urine sample (currently all samples are being investigated) | Viral PCR of lesion swab | Viral culture or viral PCR of lesion swab | Serology | Clinical | Skin biopsy showing keratinocytes with eosinophilic cytoplasmic inclusion bodies |
| Treatment | Supportive; antiviral drugs restricted to high-risk cases and are not widely available outside of a clinical trial | Acyclovir, valacyclovir | Acyclovir, valacyclovir | Penicillin | Supportive | Supportive |
Note: HSV = herpes simplex virus, PCR = polymerase chain reaction.
↵* Being challenged in the 2022 outbreak. Investigations are ongoing.