Molluscum contagiosum: chronic poxvirus infection
·
Common disease of childhood but also can occur
in adults
·
Transmitted by skin-skin contact anywhere on
body
o
sexually or in contact sports
o
scratching or touching a lesion
o
only host is humans but can be spread by fomites
on towels or swimming pools
·
Associated with immunocompromised states (HIV or
immunosuppressive drugs)
·
May be associated with atopic dermatitis
·
Incubation period typically 2-6 weeks
·
Flesh-colored, dome-shaped papules usually 2-5
mm in diameter
·
Shiny surface with central indentation or
umbilication
·
May be associated with pruritus
·
May occur anywhere on body except palms and
soles
·
Most common areas: trunk, axillae, antecubital
and popliteal fossae, and crural folds
·
Diagnose based on appearance but can do
histology to confirm
·
Lesions usually resolve within 2 months but may
take up to 1 year
·
Self-limited to technically do not need to treat
(in immunocompetent patients)
·
First-line therapy:
o
Cryotherapy – liquid nitrogen
o
Curettage – may cause scars
o
Cantharidin – topical blistering agent, without
scarring
o
Podophyllotoxin – antimitotic gel or cream
·
Second-line
o
Imiquimod – topical immunomodulator
o
Potassium hydroxide
o
Salicyclic acid
o
Topical retinoids
·
Oral cimetidine ***
o
H2 antihistamine
o
Immunomodulatory properties
§
Stimulate delayed hypersensitivity
§
T suppressor lymphocytes possess histamine
receptors
§
Cimetidine enhances cell-mediated immunity by
preventing histamine-induced stimulation of T suppressor activity but
underlying mechanism is not clearly understood
§
Has been shown to benefit in varicella zoster,
herpes simplex, mucocutaneous candidiasis, etc.
o
Dose studied: 40 mg/kg/day x 2 months –
associated with clearance of all lesions
§
Dosage less than 40 mg/kg/day was inffective for
viral warts
§
NOT a randomized placebo controlled trial
·
Need to prevent transmission
o
Cover lesions with clothing or watertight
bandage
o
Avoid sharing towels, sponges, etc
