The therapy of molluscum contagiosum is divided into three treatment groups: children, adults, and the immunosuppressed. Molluscum contagiosum limited to the genital area in children should raise the possibility of child abuse.
Children may have a few lesions or many lesions (50 to hundreds).
Over 50 lesions
- For children with many lesions, no therapy is an acceptable approach. These lesions eventually will disappear spontaneously without sequelae. Parents are reluctant to accept this option, but heroic measures are unnecessary and potentially scarring both physically and emotionally.
- In the cooperative child, cantharidin applied for 2-6 hours may cause enough irritation to cause lesions to involute.
Under 50 lesions
If the number of lesions is manageable and the child is at least in part cooperative, multiple topical therapies may work.
- Administer cryotherapy with liquid nitrogen to the individual lesions.
- Apply 1 tiny drop of cantharidin to the tip of each lesion and wash off in 2-6 hours. Do not occlude. Before allowing the patient to move around, be sure the medication is dry to the touch so it does not spread to normal skin. Lesions will crust and fall off in less than 1 week. This medication must be applied by the doctor in the office. It cannot be used in occluded areas (axillae, groin, inner thighs) or around the eyes.
- Pricking the surface of a lesion with a #11 blade will often lead to inflammation and resolution of that lesion. Pressing out the central core of the lesion with a comedone extractor will guarantee resolution.
- Cooperative children occasionally may be able to tolerate the pain of curetting individual lesions.
Molluscum contagiosum in normal adults is usually an STD and is found in the genital area. Adults with extensive lesions outside the genital area must be evaluated for immunosuppression, especially HIV infection.
- Cryotherapy with liquid nitrogen is quick and effective.
- Evaluate for other STDs.
- Examine and treat the patient's sexual partner(s).
- Advise the patient that the lesions are sexually transmissible.
- Destruction of each lesion by pricking with a large (18-guage) needle or a #11 blade. Removal of the core with a comedone extractor will enhance resolution.
- Adults will usually tolerate curettage of individual lesions.
- Electrocautery may be used to destroy smaller lesions. Anesthesia with topical EMLA may allow this form of treatment without injected anesthesia.
One treatment is usually inadequate to eradicate all lesions. See the patient at biweekly intervals until no lesions are present, then 4-6 weeks after the last visit for a final check.
- The most common error is diagnosing molluscum as genital warts. If there is any question, refer the patient.
- Avoid cantharidin in the genital area.
In severe immunosuppression, especially in advanced AIDS, extensive facial or genital molluscum are very common. Total cure is almost impossible. (Individual lesions in general do not spontaneously resolve as in healthy adults and children.) Lesions are treated for cosmesis at the patient's request.
Molluscum contagiosum in the setting of HIV infection is a direct consequence of significant immunosuppression. The treatment of choice is institution of Highly Active Antiretroviral Therapy (HAART). Once the helper T cell count exceeds 100, the molluscum begin to resolve, leaving no scars. This takes several months. Aggressive therapy that potentially would scar should not be undertaken until the full beneficial effects of immune reconstitution have been realized.
- Liquid nitrogen cryotherapy (preferably by spray rather than a swab) is effective and well tolerated for smaller lesions.
- For facial or truncal molluscum, cantharidin applied for 2-6 hours and then washed off will also resolve lesions. This has the advantage of usually being painless.
- Instruct the patient to use only an electric razor (preferably with floating heads) to shave. This type of shaving is less likely to spread the lesions.
- Pricking and curetting lesions, although also effective, have disadvantages. First, this approach is potentially hazardous to the care provider because he or she may be exposed to blood. Second, this may provide a portal of entry for infection. If these methods are used, appropriate precautions are necessary.
- 5-Fluorouracil 5% cream may cause inflammation of lesions and their gradual resolution. Treatment should be used at the frequency tolerated by the patient in order to maintain mild inflammation of the lesions. This is usually once or twice weekly in fair-skinned persons, but up to once daily in persons of color. Several months of treatment may be required.
- In severe cases, trichloroacetic acid peels, up to 50% concentration, may be considered.
In the setting of immunosuppression, other infectious agents (e.g., herpes simplex, cryptococcus neoformans) may produce lesions mimicking molluscum contagiosum. If there is any question as to the correct diagnosis, a biopsy is in
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