INTRODUCTION
Molluscum contagiosum (MC) is a common and benign contagious viral skin condition of childhood occurring worldwide. It was first described by Bateman in the beginning of the nineteenth century.1 MC currently accounts for approximately 1% of all diagnoses of skin disorders in the US2,3 with an occurrence of up to 10% in the pediatric population under age 10.4 The incidence of sexual transmission in the adult population is also rapidly increasing.5,6 In addition, between 5% and 20% of patients with HIV have symptomatic MC.7
The molluscum contagiosum virus (MCV) is a doubled-stranded DNA poxvirus with no significant animal reservoir.8-11 It is a cytoplasmically replicating virus and proliferates in the follicular epithelium.12 In immunocompetent patients the illness is self-limited and MCV infection generally does not recur.8 However, MCV exhibits an ability to avoid host defense mechanisms,13,14 and it is not unusual for lesions to persist and spread. The lesion presentation may vary from small papules that may be mistaken for atopy but more often reveal the characteristic central umbilication permitting easy identification (Figure 1).
The general recommendation for treatment is expectant management,3,12 with spontaneous resolution generally occurring in 12 to 30 months. However, lesions may spread to the face or cover extensive portions of the body, prompting the desire for treatment. Treatment options largely depend upon tissue destruction and include curettage, cryotherapy, laser, electrodessication, or application of caustics such as trichloroacetic acid, KOH, or cantharadin.15-17 Recently, topical immune modulators such as imiquimod have been used with some success.18 However, all current treatment options involve some degree of pain, discomfort, or irritation to the patient with accompanying distress to the parents of small children. In addition, treatments that rely on tissue destruction may increase the risk of infection and scarring.3,12,19 Thus, the need exists for a safe, painless, effective, and rapid treatment option.
Our previous studies with Australian lemon myrtle (Backhousia citriodora) demonstrated clearance of lesions in less than 50% of children with MC.20 However, there are more recent reports of cytotoxic effects with use of this oil.21 In an attempt to improve both safety and efficacy, we evaluated other formulations.
The essential oil of Melaleuca alternifolia (tea tree oil [TTO]) has been used topically as an antiseptic for decades,22 while chemical and therapeutic characterization of the essential oil (steam distillate) from M. alternifolia has a body of literature dating back to 1925,23demonstrating broad-spectrum antibacterial24-29 and antifungal30,31 action. Iodine has also been used topically for decades worldwide as a safe and effective topical antiseptic. The known antiseptic actions of iodine and tea tree oil, in conjunction with their long history of topical safety, prompted us to evaluate the combination of TTO and iodine as a topical treatment for MC.
We tested topical application of a tea tree oil: iodine preparation (TTO-I), TTO alone, and topical iodine alone as control in the
