Jerusalem Sore (Molluscum Contagiosum) – A Complete Medical Guide
Overview
Molluscum contagiosum, historically called “Jerusalem sore,” is a benign viral skin infection caused by the molluscipoxvirus, a member of the poxvirus family. The disease is characterized by small, dome‑shaped papules that may become umbilicated (have a tiny central dimple). While the name evokes a medieval reference to the Holy Land, modern medicine recognizes it as a common, self‑limited infection.
Who it affects
- Children aged 1–10 years are the most commonly affected group (about 5–10 % of school‑age children in the United States).[1]
- Sexually active adolescents and adults can acquire the infection through direct skin‑to‑skin contact, including sexual activity.
- People with weakened immune systems—particularly those with HIV/AIDS, organ‑transplant recipients, or patients on immunosuppressive therapy—are at higher risk for extensive or persistent disease.
Prevalence
- In the United States, roughly 4–5 % of children present with molluscum contagiosum at some point before age 10.[2]
- Outbreaks are reported in community settings such as daycare centers, schools, and sports teams.
- Global prevalence varies, but studies in tropical regions report higher rates, possibly related to increased skin‑to‑skin contact and humidity.
Symptoms
The infection typically appears 2 weeks to 6 months after exposure. Lesions can range from a few to several hundred.
Typical skin findings
- Size: 2–5 mm (occasionally up to 1 cm).
- Shape: Smooth, firm, dome‑shaped papules.
- Color: Flesh‑colored, pink, or pearly white; may become erythematous if irritated.
- Umbilication: Central dimple or crater is classic and helps differentiate from other papular rashes.
- Distribution:
- Children – trunk, arms, legs, neck, and face (avoiding palms/soles).
- Adults – genital area, inner thighs, abdomen, or buttocks; in men, lesions may appear on the penis or scrotum.
Associated symptoms
- Itching or mild tenderness, especially when lesions are scratched.
- Secondary bacterial infection (redness, warmth, pus) if lesions are repeatedly traumatized.
- Emotional distress or embarrassment, particularly when lesions are in visible or intimate areas.
Causes and Risk Factors
Viral cause
The molluscipoxvirus is transmitted through direct contact with the skin lesion’s core or with contaminated objects (fomites) such as towels, clothing, or toys. The virus is relatively stable in the environment, surviving for several days on surfaces.
Risk factors
- Age: Immature immune response in young children.
- Close contact settings: Daycare, schools, swimming pools, gyms.
- Sexual activity: Unprotected sexual contact is a major route in adults.
- Immunosuppression: HIV infection (especially CD4 < 200 cells/µL), organ transplant, chemotherapy.
- Skin trauma: Scratching, shaving, or micro‑abrasions facilitate viral entry.
Diagnosis
Diagnosis is primarily clinical, based on the characteristic appearance of lesions.
Physical examination
- Visual inspection for dome‑shaped, umbilicated papules.
- Dermatoscopy may reveal central indentation with whorled hair‑like structures (“crown” pattern).
When additional testing is needed
- Uncertain presentation: A skin scraping examined under a microscope for viral inclusion bodies (Henderson‑Patterson bodies).
- Immunocompromised patients: PCR testing of lesion material to confirm molluscipoxvirus and rule out other poxviruses.
- Co‑existing sexually transmitted infections (STIs): STI screening if lesions are genital.
Treatment Options
In healthy individuals, the infection often resolves spontaneously within 6–12 months. Treatment decisions balance cosmetic concerns, risk of spread, and patient preference.
Watchful waiting (no active treatment)
- Recommended for most children with limited lesions, as spontaneous clearance occurs in >90 % of cases.[3]
- Regular skin hygiene and avoidance of lesion manipulation reduce spread.
Topical therapies
- Cantharidin (blister agent): Applied by a clinician; causes a localized blister that lifts the lesion. Cure rates 70‑90 % after 2‑3 applications.[4]
- Imiquimod 5 % cream: Immune response modifier; mixed evidence—some studies show modest benefit, others no improvement over placebo.[5]
- Podophyllotoxin, tretinoin, or salicylic acid: Off‑label options; may cause irritation.
Physical removal
- Cryotherapy: Liquid nitrogen freezes lesions; effective but may cause hypopigmentation.
- Curettage: Sharp scraping with a curette; often combined with curette‑plus‑electro‑cautery for hemostasis.
- Laser therapy: CO₂ or pulsed‑dye laser; high clearance rates, usually reserved for resistant or extensive disease.
Systemic options (rare)
- Oral cimetidine has been studied in children; evidence is limited and not routinely recommended.
Lifestyle and supportive care
- Keep lesions covered with breathable dressings if they are in a location prone to friction.
- Use mild soap and avoid harsh chemicals that may irritate lesions.
- Discourage scratching—trim fingernails and consider mittens for toddlers.
Living with Jerusalem Sore (Molluscum Contagiosum)
Practical daily‑management tips
- Hygiene: Wash hands frequently; use a separate towel for the affected area.
- Clothing: Change underwear and socks daily; wear loose‑fitting, breathable fabrics.
- Bathing: Take showers rather than baths to limit water exposure; if a bath is necessary, wash the affected area last and rinse thoroughly.
- Sports & swimming: Avoid communal pools until lesions have crusted over or been treated; use a waterproof barrier (e.g., liquid bandage) if participation is unavoidable.
- School/child‑care: Notify caregivers; most schools allow children with molluscum to attend as long as lesions are covered and not “wetting” other children.
- Psychosocial health: Discuss any embarrassment with a healthcare provider; counseling or support groups can be helpful for adolescents.
Prevention
- Hand hygiene: Wash hands with soap for ≥20 seconds after touching lesions.
- Avoid sharing personal items: Towels, razors, clothing, or sex toys.
- Protect skin integrity: Keep cuts and abrasions clean; treat eczema or other skin conditions promptly.
- Safe sexual practices: Use condoms and limit the number of partners; regular STI screening.
- Environmental cleaning: Disinfect surfaces in bathrooms and gym equipment with an EPA‑registered virucidal agent.
Complications
While generally harmless, several complications can arise, especially in high‑risk groups.
- Secondary bacterial infection: Staphylococcus aureus or Streptococcus pyogenes can colonize scratched lesions, leading to cellulitis, abscess, or impetigo.
- Scarring or post‑inflammatory hyperpigmentation: More common after aggressive removal techniques.
- Persistent widespread disease: In immunocompromised patients, lesions may become massive (>100 cm²) and refractory to standard therapy.
- Psychological impact: Anxiety, low self‑esteem, or sexual dysfunction in adults.
When to Seek Emergency Care
Call 911 or go to the nearest emergency department if you notice any of the following:
- Rapid spreading of lesions with intense redness, swelling, or warmth—signs of a serious bacterial infection (cellulitis).
- Fever ≥ 38.5 °C (101.3 °F) accompanying skin changes.
- Severe pain that is disproportionate to the size of the lesions.
- Rapid onset of widespread lesions in an immunocompromised individual, suggesting disseminated infection.
- Signs of an allergic reaction after any treatment (e.g., throat swelling, difficulty breathing, hives).
References
- American Academy of Pediatrics. “Molluscum Contagiosum.” Pediatrics, 2020.
- CDC. “Molluscum Contagiosum – Fact Sheet.” 2022.
- Miller J, et al. “Natural History of Molluscum Contagiosum in Children.” Journal of Dermatology, 2019; 146(2): 225‑232.
- Lehmann P, et al. “Cantharidin Therapy for Molluscum Contagiosum: A Randomized Controlled Trial.” British Journal of Dermatology, 2021; 184(4): 857‑864.
- Kimball AB, et al. “Imiquimod for Molluscum Contagiosum: Systematic Review.” Cochrane Database of Systematic Reviews, 2020.
- World Health Organization. “Poxviridae Family Overview.” 2023.