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Concept: Cantharidin


Cantharidin is a widely used treatment for molluscum contagiosum (MC) that is often favored because of its speed of application and lack of pain at the time of application. Previous studies have supported its safety and reported high parental and dermatologist satisfaction with its use. Nonetheless, a lack of safety data has contributed to ambiguous U.S. Food and Drug Administration status that has made it increasingly difficult to obtain. All children treated with cantharidin for MC at a tertiary care center between January 1, 2005, and December 31, 2011, who had at least one follow-up visit or telephone call were included in the current study. Information related to treatment with cantharidin and adverse effects was abstracted from medical records. Of 512 children identified, 405 had at least one follow-up visit or telephone call after treatment and were included in this study. Cantharidin was applied to 9,688 lesions over 1,056 visits. Fifty-seven percent of children experienced blistering, an expected effect of therapy. Eleven percent of patients experienced adverse events. The most common adverse events were pain (7%) and significant blistering (2.5%). Other side effects were rare (<1%) and included pruritus, possible mild infection, significant irritation, id reactions, and bleeding. Eighty-six percent of parents reported satisfaction with cantharidin or opted to use it again. Cantharidin is a safe treatment modality for MC and should be considered when symptomatic infection necessitates treatment. The cantharidin application protocol used in this study may serve as a model protocol with a known side-effect profile.

Concepts: Immune system, Medicine, Adverse effect, Tertiary referral hospital, Molluscum contagiosum, Iatrogenesis, Wart, Cantharidin


Leflunomide (LEF) is an immune modulator used most commonly for rheumatoid arthritis (RA). The mechanisms of action of LEF also include anti-microbial effects, particularly anti-viral effects.
OBSERVATIONS: We present three patients with atopic dermatitis on azathioprine therapy who had multiple verrucae and in two molluscum contagiosum (MC) that were resistant to repeated conventional therapies. These patients were switched to LEF, and all the patients showed complete resolution of their verrucae and MC within 2 months of starting therapy. In addition, all three patients showed equivalent to better control of their atopic dermatitis with LEF.
CONCLUSIONS: LEF has previously been reported to be a useful immune modulator for the treatment of severe atopic dermatitis. The spectrum of anti-viral effects previously seen with leflunomide did appear beneficial in these patients in clearing verrucae and MC, which had been resistant to conventional therapies while the patients were on azathioprine.

J Drugs Dermatol. 2015;14(3):230-234.

Concepts: Inflammation, Rheumatoid arthritis, Rheumatology, Molluscum contagiosum, Psoriatic arthritis, Atopic dermatitis, Wart, Cantharidin


Warts and molluscum contagiosum are very common viral skin infections, usually presenting in childhood. Despite the large number of people affected by them, high-quality trials of treatment are few and treatment is often chosen on the basis of cost, convenience and tradition.

Concepts: Infectious disease, Molluscum contagiosum, Number names, Wart, Virus-related cutaneous conditions, Cantharidin


Pediatric skin and soft tissue infections (SSTIs) constitute a significant number of office-based pediatric visits. With SSTIs on the rise, it is not only important to effectively treat the individual, but to do so appropriately and cost-consciously. In this article, we highlight new research related to the treatment of bacterial skin infections, molluscum contagiosum, and cutaneous warts, with the goal of guiding pediatricians in their practice against these common skin conditions.

Concepts: Staphylococcus, Tissues, Skin, Tissue, Molluscum contagiosum, Wart, Virus-related cutaneous conditions, Cantharidin


Inverted follicular keratosis is a benign follicular tumor. Tumors classically demonstrate lobulated, endophytic growth with squamous eddy formation. The histologic differential diagnosis includes irritated seborrheic keratosis, trichilemmoma, verruca vulgaris, squamous cell carcinoma, and keratoacanthoma. The clinical differential diagnosis includes verruca, molluscum contagiosum, follicular cyst, and squamous cell carcinoma. In the past, a predilection for the head and neck of elderly men has been reported. Our experience is that the age, gender, and anatomic distribution of this lesion are more varied. Herein, we describe five cases of inverted follicular keratoses of the buttocks in middle-aged persons of both genders. These cases highlight the importance of considering inverted follicular keratosis as a possible buttock lesion because of its benign nature, in contrast to its clinical and histologic mimics. In addition, these cases are unique and relevant to the study of dermatopathology because they demonstrate a different age, gender, and anatomic distribution than previously reported.

Concepts: Cancer, Anatomical pathology, Squamous cell carcinoma, Molluscum contagiosum, Epidermal nevi, neoplasms, cysts, Wart, Seborrheic keratosis, Cantharidin


Commonly known as blister beetles or Spanish fly, there are more than 1,500 species in the Meloidae family (Hexapoda: Coleoptera: Tenebrionoidea) that produce the potent defensive blistering agent cantharidin. Cantharidin and its derivatives have been used to treat cancers, such as liver, stomach, lung and esophageal cancers. Hycleus cichorii and Hycleus phaleratus are the most commercially important blister beetles in China due to their ability to biosynthesize this potent vesicant. However, there is a lack of genome reference, which has hindered development of studies on the biosynthesis of cantharidin and a better understanding of its biology and pharmacology.

Concepts: Gene, Organism, Species, Insect, Beetle, Beetles, Blister beetle, Cantharidin


Molluscum contagiosum (MC) is an infectious dermatosis that commonly presents in children and immunocompromised individuals. Although lesions usually resolve spontaneously after several months, they can be symptomatic and cause psychosocial distress. We review the evidence underlying treatment methods available for MC lesions, including potassium hydroxide, salicylic acid, hydrogen peroxide, retinoids, cantharidin, cryotherapy, curettage, and pulsed dye laser to aid practicing dermatologists in therapy selection.

Concepts: Oxygen, Laser, Chlorine, Molluscum contagiosum, Base, Potassium hydroxide, Wart, Cantharidin


A literature review and clinical commentary on diagnosis and treatment of common childhood bacterial, fungal and viral skin infections is presented including impetigo, folliculitis, staphylococcal scalded skin syndrome, tinea capitis, warts and molluscum contagiosum.

Concepts: Bacteria, Staphylococcus aureus, Staphylococcus, Molluscum contagiosum, Wart, Staphylococcal scalded skin syndrome, Bacterium-related cutaneous conditions, Cantharidin


Glutathione S-transferases (GSTs) play a key role in detoxification of xenobiotics in organisms. However, their other functions, especially response to the natural toxin cantharidin produced by beetles in the Meloidae and Oedemeridae families, are less known. We obtained GST cDNAs from three sources: Cydia pomonella (CpGSTd1), Sus scrofa (SsGSTα1), and Triticum aestivum (TaGSTf3). The predicted molecular mass is 24.19, 25.28 and 24.49kDa, respectively. These proteins contain typical N-terminal and C-terminal domains. Recombinant GSTs were heterologously expressed in Escherichia coli as soluble fusion proteins. Their optimal activities are exhibited at pH 7.0-7.5 at 30°C. Activity of CpGSTd1 is strongly inhibited by cantharidin and cantharidic acid, but is only slightly suppressed by the demethylated analog of cantharidin and cantharidic acid. Enzymatic assays revealed that cantharidin has no effect on SsGSTα1 activity, while it significantly stimulates TaGSTf3 activity, with an EC50 value of 0.3852mM. Activities of these proteins are potently inhibited by the known GST competitive inhibitor: S-hexylglutathione (GTX). Our results suggest that these GSTs from different sources share similar structural and biochemical characteristics. Our results also suggest that CpGSTd1 might act as a binding protein with cantharidin and its analogs.

Concepts: DNA, Protein, Metabolism, Escherichia coli, PH, Toxin, Glutathione S-transferase, Cantharidin


Background: Cantharidin is a topical vesicant that causes intraepidermal acantholysis with clinical application that includes the removal of warts, molluscum contagiosum (MC), calluses, and acquired perforating dermatoses. Objective: To provide a comprehensive literature review of the efficacy and safety of cantharidin in the management of various cutaneous conditions. Methods: A PubMed search was conducted using the term “cantharidin” combined with “warts”, “plantar warts”, “verruca vulgaris”, “periungal”, “subungual”, “topical treatment”, “topical therapy for warts”, molluscum contagiosum", “perforating collagenosis,” and “acantholysis.” Results: A total of 749 articles were identified and 37 articles met inclusion criteria for this review. The majority of studies show that cantharidin is an effective and safe treatment for removal of warts and MC. Several studies also show potential novel applications of cantharidin in acquired perforating dermatosis, acute herpes zoster, and leishmaniasis. Adverse effects are generally mild but common and should be monitored, particularly in the pediatric population. Limitations: There is a paucity of high-powered clinical studies involving the use of cantharidin. Conclusion: Topical cantharidin is a safe and effective treatment for warts, molluscum contagiosum, and callus removal, with promising uses in perforating dermatoses and leishmaniasis.

Concepts: Effectiveness, Salicylic acid, Molluscum contagiosum, Blister, Plantar wart, Wart, Virus-related cutaneous conditions, Cantharidin