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Treatment of multiple seborrheic keratoses (SKs) can present many challenges. SKs can be bothersome, with many patients complaining of pruritus in the involved areas. They can also be cosmetically unattractive, especially in patients with a dominantly inherited genetic predisposition to multiple lesions (medical conditions such as the Lesser-Trelat sign will not be discussed here).

Patients are often surprised to learn that SKs can be removed, often with minimal scarring. Currently, the most common modes of treatment for SKs are cryosurgery and electrodessication.

Limitations of treatment with cryosurgery or electrodessication, particularly on the face and neck, are pain and post-inflammatory hyperpigmentation in darker skin types. In addition, most patients can only tolerate treatment of a few lesions at one time on the face and neck , due to discomfort. Dermatosis Papulosa Nigra (DPN) is even more challenging to treat due to numerous and small lesions, with local or topical anesthetic and hyfercation of multiple areas both impractical and difficult for patients to tolerate.

An ideal treatment for SK would have little to no pain, be able to treat numerous lesions, and present little risk of scarring and hyperpigmentation.The first and only medication FDA approved to treat SKs is Eskata (40% hydrogen peroxide, Aclaris), which was recently withdrawn from the market.

This article will discuss the use of WartPeel (5-FU 2.5%/Salicylic Acid 17%, MedCara Pharmaceuticals), a compounded topical medication which we have previously described in detail for the treatment of verrucae.

Wartpeel offers 5-FU (2.5%) and salicylic acid (17%) in the Remedium Delivery System. According to the patent application, it is “75% by weight of an adhesive; whereby the composition is a sustained release topical gel that releases salicylic acid onto the wart for removal of keratin of the wart and surrounding skin to allow penetration of the 5-FU into the wart.” It is available by mail order (in most states).

At the time our original article was written, we had used it on moroe than 100 patients and found it to have a cure rate of greater than 90 percent in one to two weeks. Since then we have treated hundreds more patients and have observed a similar cure rate when used properly. It continues to be a first-line treatment. The histology of both SKs and verrucae is primarily epidermal, and thus it is not surprising that 5-FU 2.5%/salicylic acid 17% works well for these lesions as well.

We have had success using 5-FU 2.5%/salicylic acid 17% as a guided at-home treatment for SKs, with weekly follow ups. A 5ml tube can treat one to two dozen lesions (depending on their size), which is cost-effective for patients.

Figure 1. Patient with SKs at basline.
Figure 2. Patient following 7 days of application of 5-FU 2.5%/salicylic acid 17%.
Figure 3. Patients shown 2 weeks after an additional round of treatment of residual lesions.

The protocol we have developed for treating SKs is similar to that for wart treatment. Skipped days are a common cause of treatment failure for warts because they aggressively grow back. However, this does not occur with SKs.The average treatment time is three to seven days depending on the size and thickness of the lesion. The medication is put on at night and allowed to fully dry (10-15 minutes); it is washed off in the morning. To avoid excess irritation, it is important that the formulation does not move off the SK and on to normal skin. We reinforce this by applying it in the office to demonstrate. It can be applied directly from the syringe it comes in, or the applicator provided can be used for smaller lesions. Stinging attributable to the salicylic acid will occur for 15 to 30 minutes but it is tolerable for the vast majority of patients. If the stinging is bothersome to the patient we advise them to use OTC 20% benzocaine 30 minutes before application. A fan or hair dryer can accelerate drying if desired.

Scarring can potentially occur from 5-FU 2.5%/salicylic acid 17% if tissue destruction occurs beyond the epidermis. This is why weekly follow up and patient education are important. We advise patients to discontinue if the lesion gets painful or inflamed, as that is a sign the 5-FU/salicylic acid has destroyed the SK or wart and is starting to impact uninvolved skin. We also advise to discontinue when the lesion becomes flat or it peels off and has no visible lesion underneath. With these instructions and weekly follow up, we have not had any cases of scarring to date.

Hyperpigmentation can also occur but is minimal and less severe than that seen with cryosurgery or ED&C. Hydrocortisone 2.5% ointment can be used each morning after 5-FU/aalicylic acid is washed off to reduce irritation and hyperpigmentation. When we fax the prescription in we specify that it is for SK and to not include the tape that is normally included with the product. The tape is used chiefly for palmoplantar warts and has no benefit for SKs.

On follow-up the patients can be told which lesions need further treatment. Gentle curettage can be performed. With large SKs often the center can be easily removed and the patient may need to continue treatment on the more adherent border for a few more days.The patient can be instructed to gently rub the treated lesions with a warm washcloth to encourage the dead SK to separate from the skin. By the second follow up, most SKs are resolved. As the patient gains experience, he or she can treat additional lesions, diagnosed by a medical professional, either on their own or with continued follow up.

The patient whose photos are shown returned one week after using WartPeel for seven days. His SKs prior to treatment were severe, and great improvement was seen. Some of the larger darkly pigmented lesions were completely resolved. Others were improved, with thin residual SKs remaining. The patient presented for follow up one additional time two weeks later having treated additional lesions. The patient was educated of which lesions needed more treatment and felt confident enough to choose to continue treatment at home without additional follow up.

As with treatment of warts, SK patients were extremely satisfied with their experience, due to ease of use, and rapid results with mild discomfort. WartPeel can be a cost effective option when compared to in-office treatments.For patients with needle phobia, it may be the only option.It can also be a patient’s first introduction to aesthetic procedures. During follow-up visits, patients asked questions about other ways their appearance could be improved, such as removal of lentigines, benign nevi, acrocordons, treatment of melasma, and addressing facial lines. Thus, 5-FU 2.5%/Salicylic Acid 17% has become a first line treatment in our practice not only for warts, but SKs as well.

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