Molluscum contagiosum

Molluscum contagiosum is a cutaneous poxvirus infection. It is spread by skin-to-skin contact and less often by fomites. The three populations affected are: self-limited in children (highest prevalence in 1-4 year olds); sexually transmitted in adults; and in AIDS patients.

CASES/YEAR
720,000 (US); 14,400,000 (Global)
AGENT TYPE
Viruses
OTHER NAMES
ACUITY
Acute-Moderate
INCUBATION
19-50 days (after experimental inoculation); 7 days to 6 months (from clinical reports); [CCDM, p. 415]
INITIAL SYMPTOMS
Papules occur anywhere on the body except palms & soles; Patterns are genital (adults), exposed skin (children), & more severe (AIDS-related) [Merck Manual, p. 1082, 1728] Infrequently on the palms; [ID, p. 1984] May occur on palms; [Guerrant, p. 1037]
PRECAUTIONS
Standard
COMMENTS
Skin lesions are as large a 10 mm, but usually 2 to 3 mm in diameter. They are pearly papules, umbilicated, with a waxy surface. This cutaneous poxvirus infection is spread by skin-to-skin contact and less often by fomites. The three populations affected are: 1. self-limited in children (highest prevalence in 1-4 year olds); 2. an STD in adults; and 3. in AIDS patients. More common in tropical climates; [ABX Guide] Lesions are smooth-surfaced, firm, spherical 2-5 mm papules that occasionally may be as large as 10-30 mm. Most common locations are the lower abdominal, pubic, genital, and inner thighs in adults and the face, trunk and proximal extremities in children. [CCDM, p. 414] May be complicated by conjunctivitis or punctate keratitis; Rarely on palms & soles; [Cohen, p. 1453-4] Typically multiple lesions are found in the genital area (inguinal or inner thigh) or in other areas (palms, soles, eyelids, and conjunctiva); AIDS patients may have extensive face and torso involvement. [Guerrant, p. 1037] AIDS patients may have hundreds of lesions. [Cecil, p. 2622] Highly prevalent in children; Swimming pools are a common source of infection. Usually resolve within 3-4 months in immunocompetent patients, but may persist for 3-5 years; [Harrison ID, p. 762]
DIAGNOSTIC
Clinical; Can be confirmed by routine histological examination--molluscum bodies visible in cytoplasm of epithelium; [ABX Guide]
SCOPE
Global
SIGNS & SYMPTOMS
  • O conjunctivitis, acute
  • S papules or plaques
  • S rash on palms
ANTIMICROBIC

No

VACCINE

No

ENTRY
Skin or Mucous Membranes (Includes Conjunctiva), Sexual Contact
SOURCE
Person-to-Person
RESERVOIR
Human
RISK FACTORS
  • AIDS patients
TREATMENT
Reassure parents that this is a benign skin condition of childhood that resolves spontaneously. [ABX Guide] It usually takes 6-9 months or up to 3 years for lesions to resolve without treatment. Treatment options include curettage and cryosurgery. "Imiquimod is usually not recommended. . . . Cantharidin is safe and effective but can cause blistering." [Merck Manual, p. 1082]
REFERENCES FOR CASES/YEAR
1. (US) 1/20 of global cases/yr = 720,000
2. (Global) 90% of cases were in children aged 0-14 years; About 24 cases/10,000/year was the rate observed in a study of 1/2 million people observed every year from 1994-2003 in England and Wales; [PMID 16274495] Calculate: 24/10,000 X 6 trillion = 14,400,000;