Molluscum contagiosum is characterized by clusters of pink, dome-shaped, smooth, waxy, or pearly and umbilicated papules 2 to 5 mm in diameter caused by molluscum contagiosum virus, a poxvirus. Diagnosis is based on clinical appearance. Treatment is aimed at preventing spread or removing cosmetically unacceptable lesions and can include mechanical methods (eg, curettage, cryosurgery) and topical irritants (eg, cantharidin, tretinoin).
Molluscum contagiosum virus commonly causes a localized chronic infection. Transmission is by direct contact; spread occurs by autoinoculation and via fomites (eg, towels, bath sponges) and bath water. Adults acquire the infection via close skin-to-skin contact with an infected person (eg, sexual contact, wrestling).
Patients with immunocompromise (eg, due to HIV/AIDS, corticosteroid use, or chemotherapy) may develop a more widespread infection (1, 2).
Molluscum contagiosum is common among children.
Довідкові матеріали загального характеру
1. Meza-Romero R, Navarrete-Dechent C, Downey C: Molluscum contagiosum: An update and review of new perspectives in etiology, diagnosis, and treatment. Clin Cosmet Investig Dermatol 12:373–381, 2019. doi: 10.2147/CCID.S187224
2. Edwards S, Boffa MJ, Janier M, et al: 2020 European guideline on the management of genital molluscum contagiosum. J Eur Acad Dermatol Venereol 35(1):17–26, 2021. doi: 10.1111/jdv.16856
Symptoms and Signs of Molluscum Contagiosum
Molluscum contagiosum can appear anywhere on the skin except the palms and soles. Lesions consist of clusters of pink, dome-shaped, smooth, waxy, or pearly and umbilicated papules, usually 2 to 5 mm in diameter, which occur most commonly on the face, trunk, and extremities in children and on the pubis, penis, or vulva in adults. Lesions may grow to 10 to 15 mm in diameter, especially among patients with HIV infection and other immunodeficiencies.
Lesions are usually not pruritic or painful and may be discovered only coincidentally during a physical examination. However, the lesions can become inflamed and itchy as the body fights off the virus.
The photo shows lesions of molluscum contagiosum. Lesions are typically 1 to 5 mm, solitary or grouped, firm, painless papules. They are pearly to pink in color, dome shaped, and may be umbilicated.
© Springer Science+Business Media
This image shows scattered lesions of molluscum contagiosum on the lateral torso of a toddler.
Image courtesy of James G.H. Dinulos, MD.
This photo shows very severe lesions on the face of a child with HIV infection. Giant molluscum indicates advanced immunodeficiency.
© Springer Science+Business Media
Diagnosis of Molluscum Contagiosum
Clinical evaluation
Diagnosis of molluscum contagiosum is based on clinical appearance; skin biopsy or smear of expressed material shows characteristic inclusion bodies but is necessary only when diagnosis is uncertain.
Differential diagnosis includes folliculitis, milia, and warts (for lesions < 2 mm) and juvenile xanthogranuloma and Spitz nevus (for lesions > 2 mm).
Treatment of Molluscum Contagiosum
Physical removal: Curettage, cryosurgery, laser therapy, or electrocautery
Topical irritants (eg, trichloroacetic acid, cantharidin, tretinoin, tazarotene, podophyllotoxin [podofilox])
Sometimes intralesional injection or photodynamic therapy
Sometimes combination therapies
Most lesions spontaneously regress in 1 to 2 years, but they can remain for 2 to 3 years.
Treatment of molluscum contagiosum is indicated for cosmetic reasons or for prevention of spread. Options include curettage, cryosurgery, laser therapy, electrocautery, trichloroacetic acid (25 to 40% solution), cantharidin, podophyllotoxin (podofilox) in adults, tretinoin, and tazarotene. Some clinicians use salicylic acid, but others consider it too irritating for many body areas where molluscum occurs. Similar concerns exist with use of potassium hydroxide (KOH). Small studies suggest that ingenol mebutate gel, a cytotoxic agent used to treat actinic keratoses, may be effective (1). Molluscum lesions within the orbital rim should be removed via gentle destruction by a skilled clinician. Lesions may be gently squeezed with a forceps to remove the central core. Treatments that cause minimal pain (eg, tretinoin, tazarotene, cantharidin) are used first, especially in children. Imiquimod is usually not recommended.
Curettage or liquid nitrogen can be used 40 to 60 minutes after application of a topical anesthetic such as EMLA (lidocaine/prilocaine) cream or 4% lidocaine cream under an occlusive dressing. EMLA cream must be applied judiciously because it can cause systemic toxicity, especially in children. In adults, curettage is very effective but painful if done without anesthetic.
Cantharidin is safe and effective but can cause blistering. It is applied in 1 small drop directly to the molluscum lesion. Areas that patients (especially children) may rub are covered with a bandage because contact with the fingers should be avoided. Cantharidin should not be applied to the face or near the eyes because blistering is unpredictable. If cantharidin comes into contact with the cornea, it can cause scarring. Cantharidin should be washed off with soap and water in 6 hours. Fewer than 15 lesions should be treated in one session because infection may occur after application of cantharidin. Parents should be warned about blistering if their children are prescribed this irritant.
Other treatments include intralesional injection (eg, with Candida antigen or occasionally interferon alpha; 2) and photodynamic therapy. Antiviral and immunomodulatory medications have been more successful in patients infected with HIV (3).
Dermatologists often use combination therapy such as liquid nitrogen or cantharidin in the office or a retinoid cream at home. This form of therapy is typically successful, but resolution often takes 1 to 2 months in some patients.
Children should not be excluded from school or day care. However, their lesions should be covered to reduce the risk of spread.
Довідковий матеріал щодо лікування
1. Shin K, Bae KN, Kim HS, et al: Ingenol mebutate gel for the treatment of molluscum contagiosum: An open-label comparative pilot study. J Am Acad Dermatol pii:S0190-9622(19)32689-1, 2019. doi: 10.1016/j.jaad.2019.08.081
2. Wells A, Saikaly SK, Schoch JJ: Intralesional immunotherapy for molluscum contagiosum: A review. Dermatol Ther 33(6):e14386, 2020. doi: 10.1111/dth.14386
3. Vora RV, Pilani AP, Kota RK: Extensive giant molluscum contagiosum in a HIV positive patient. J Clin Diagn Res 9(11):WD01-2, 2015. doi: 10.7860/JCDR/2015/15107.6797
Ключові моменти
Molluscum contagiosum, caused by a poxvirus, commonly spreads by direct contact (eg, sexual contact, wrestling), fomites, and bath water.
Lesions tend to be asymptomatic clusters of 2- to 5-mm diameter papules that are pink, dome-shaped, smooth, waxy, or pearly and umbilicated.
Diagnose based on clinical appearance.
Treat for cosmetic reasons or prevention of spread.
Treatments can include destructive methods (eg, curettage, cryosurgery, laser therapy, electrocautery) or topical irritants (eg, trichloroacetic acid, cantharidin, tretinoin, tazarotene, podophyllotoxin).