Unconventional treatments for warts and molluscum

“Is it not a strange fate that we should suffer so much fear and doubt for so small a thing? So small a thing!” –J.R.R. Tolkien, The Fellowship of the Ring

Peter Lio, M.D.Boromir, Captain of the White Tower, was referring to the one Ring of course, but his words could perhaps equally apply to warts and molluscum. Indeed, despite the fact that these small viral growths are benign and self-limited, they are responsible for some 21% of all dermatology referrals¹ and a disproportionately large amount of angst and worry.

Check out: The good, the bad, the ugly of alternative therapies

Disconcertingly perhaps, one does not need to seek an alternative medicine source to witness an incredible menagerie of strange and unconventional treatments posited for treating warts and molluscum; everything from antacids to duct tape has been tried, and entire books on the topic exist.²

While the general approach to treatment seems to focus on stimulating the innate immune response via destructive measures or irritation³, the fact that in trials even the best therapies rarely show greater than 60% clearance means there will be sizeable demand for unconventional approaches.

Check out: Honey's use in skin therapy

We will explore several alternatives for treating warts and molluscum, but I would stress that these are best used as complementary/adjunctive therapies rather than as stand-alones.

NEXT: Warts 

Warts

Zinc, as an oral supplement, may play a role in enhancing immunity, particularly against viral infections⁴. In a study of 31 patients with warts, administration of oral zinc (as zinc sulfate) resulted in complete resolution in half the patients⁵. A more rigorous randomized placebo-controlled trial of 32 patients with multiple, recalcitrant warts found that by 2 months 78% of the zinc group was cleared versus only 13% of the placebo control, a statistically significant difference⁶.  In each of these studies, the zinc sulfate was dosed at 10mg/kg/d up to a maximum of 600 mg/d, and nausea was noted to be a significant side effect.

Interestingly, although zinc is listed favorably in the venerable and quite conventional Cochrane database, one of the authors of the review has expressed skepticism about zinc for warts despite the data⁷. Perhaps most clinically relevant, zinc was shown to be a helpful adjuvant therapy in the treatment of vulvar warts. In a study of 228 patients, relapse was significantly lower in those who received concomitant oral zinc sulfate versus those who received conventional therapy alone⁸. The idea that there may be zinc deficiency in some patients with refractory warts is compelling, and this has been found in some series⁹. Further work may help ascertain patients for whom zinc can be more helpful.

Check out: Tea tree oil: What can it do for your patients?

More exotic than zinc, perhaps, is propolis: a resinous mixture used by bees to seal their hives. Remarkably, there is some evidence that propolis has immunomodulatory functions¹⁰, and it has been shown to have a positive effect in the treatment of aphthous stomatitis, mouth ulceration, and the prevention of otitis media¹¹. A fairly large study demonstrated an effect on warts as well. 135 patients were randomized to receive propolis daily for 3 months versus a placebo control group. At the end of 3 months, 73% of patients in the propolis group were cured, compared to only 8% in the placebo group, an impressive finding, indeed¹². While thought-provoking, more studies need to be done to substantiate these results, but the fact that propolis is safe and inexpensive is encouraging, although it should be avoided in those with bee allergy.

NEXT: Molluscum

Molluscum

These tiny dome-shaped papules show a predilection for children with atopic dermatitis, suggesting that impaired skin barrier can enhance their spread¹³. Maddeningly, they often induce an associated dermatitis that makes for a difficult chicken-or-egg situation, with increasing misery for the patient. Finally, a staphylococcal superinfection can develop, forcing anyone to question just how “benign” and “self-limited” this condition really is.

While warts seem to have a more distinguished cannon of conventional therapy, the literature for molluscum is relatively sparse. I adamantly agree with Dr. Katz that imiquimod is not effective for molluscum, and, in fact, can cause significant harm¹⁴. Several years ago we reported a case of cytokine dermatitis and febrile seizure resulting in hospitalization from imiquimod applied to molluscum¹⁵. Cantharidin (an extract of the blister beetle) remains my favorite therapy, although it has never been FDA-approved and can be difficult to obtain, driving the need for other options.

Check out: Skin barrier benefits of sunflower seed oil

Lemon myrtle (Backousia citriodora) is an essential oil that is used in foods and perfumes. It has been shown to have antimicrobial properties which may be relevant to its action on molluscum¹⁶. In a study of 31 children, 56% of those treated with once daily application of lemon myrtle had a 90% reduction in molluscum, compared to none in the control group¹⁷. The treatment appeared safe and was well-tolerated, suggesting that this could be a promising approach.

Tea tree oil (Melaleuca alternifolia) has antimicrobial properties and also can be irritating, both of which could theoretically be of help in molluscum. A provocative study examined tea tree oil for molluscum, but complicated things slightly by adding iodine to it without clear purpose for one of the groups, though this was a proprietary product in the study. Fifty-three children with molluscum were treated twice daily with tea tree oil bound to iodine compared to tea tree oil alone or iodine alone. At 4 weeks they evaluated for 90% clearance of molluscum and found that 56% met this mark in the tea tree oil plus iodine group, while only 17% in the pure tea tree oil group and 6% in the iodine group met this goal¹⁸. The authors reported no adverse effects, although there are multiple reports of contact allergy to topically applied tea tree oil, and this must be considered¹⁹.

Conclusion

Warts and molluscum have probably been with humans since the very beginning, and will likely continue to plague us. Like the common cold, we are somewhat powerless to stop them completely, but there are perhaps some useful tools in our alternative armamentarium yet.

References

1. Boull C, Groth D. Update: treatment of cutaneous viral warts in children. Pediatr Dermatol. 2011;28:217–29.

2. Bunney MH, Benton C, Cubie HA. Viral warts: biology and treatment, Second edition. Oxford, UK: Oxford University Press, 1992. 


3. Micali G, Dall'oglio F, Nasca MR, Tedeschi A. Management of cutaneous warts: an evidence-based approach. Am J Clin Dermatol. 2004;5(5):311-7.

4. Overbeck S, Rink L, Haase H. Modulating the immune response by oral zinc supplementation: a single approach for multiple diseases. Arch Immunol Ther Exp (Warsz). 2008 Jan-Feb;56(1):15-30.

5. Mun JH, Kim SH, Jung DS, Ko HC, Kim BS, Kwon KS, Kim MB. Oral zinc sulfate treatment for viral warts: an open-label study. J Dermatol. 2011 Jun;38(6):541–5. 


6. Yaghoobi R, Sadighha A, Baktash D. Evaluation of oral zinc sulfate effect on recalcitrant multiple viral warts: a randomized placebo-controlled clinical trial. J Am Acad Dermatol. 77 2009 Apr;60(4):706–8.

7. Gibbs S. Zinc sulphate for viral warts. Br J Dermatol 2003; 148:1082-1083.

8. Akhavan S, Mohammadi SR, Modarres Gillani M, Mousavi AS, Shirazi M. Efficacy of combination therapy of oral zinc sulfate with imiquimod, podophyllin or cryotherapy in the treatment of vulvar warts. J Obstet Gynaecol Res. 2014 Oct;40(10):2110-3

9. Raza N, Kahn DA. Zinc deficiency in patients with persistent viral warts. J Coll Physicians Surg Pak 2010; 20:83-86.

10. Sforcin J. Propolis and the immune system: a review. J Ethnopharmacol. 2007;113(1):1–14.

11. Henatsch D, Wesseling F, Kross KW, Stokroos RJ. Honey and Beehive Products in Otorhinolaryngology: a narrative review. Clin Otolaryngol. 2015 Oct 9. doi: 10.1111/coa.12557.

12. Zedan H, Hofny ER, Ismail SA. Propolis as an alternative treatment for cutaneous warts. Int J Dermatol. 2009 Nov;48(11):1246–9.

13. Braue A, Ross G, Varigos G, et al. Epidemiology and impact of childhood molluscum contagiosum: a case series and critical review of the literature. Pediatr Dermatol. 2005;22:287–94.

14. Katz KA. Imiquimod is not an effective drug for molluscum contagiosum. Lancet Infect Dis. 2014 May;14(5):372-3.

15. Mosher JS, Lio P. Cytokine dermatitis and febrile seizure from imiquimod. Pediatrics. 2012 Feb;129(2):e519-22.

16. Hayes AJ, Markovic B. Toxicity of Australian essential oil Backhousia citriodora (Lemon myrtle). Part 1. Antimicrobial activity and in vitro cytotoxicity. Food Chem Toxicol. 2002;40(4):535–43.

17. Burke BE, Baillie JE, Olson RD. Essential oil of Australian lemon myrtle (Backhousia citriodora) in the treatment of molluscum contagiosum in children. Biomed Pharmacother. 2004 May;58(4):245–7. 


18. Markum E, Baillie J. Combination of essential oil of Melaleuca alternifolia and iodine the treatment of molluscum contagiosum in children. J Drugs Dermatol. 2012 Mar;11(3):349–54.

19. Zug KA, Warshaw EM, Fowler JF Jr, Maibach HI, Belsito DL, Pratt MD, Sasseville D, Storrs FJ, Taylor JS, Mathias CG, Deleo VA, Rietschel RL, Marks J. Patch-test results of the North American Contact Dermatitis Group 2005-2006. Dermatitis. 2009 May-Jun;20(3):149-60.