How To Handle Common Skin Dermatoses

Volume 15 - Issue 9 - September 2002
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Start Page: 61

Continuing Education Course #103 — September 2002

I am very pleased to introduce the third article, “How To Handle Common Skin Dermatoses,” in our new CE series. This series, brought to you by HMP Communications, consists of regular CE activities that qualify for one continuing education contact hour (.1 CEU). Readers will not be required to pay a processing fee for this course.

Obviously, podiatrists see plenty of dermatological conditions every day in their practice. In this article, Dr. James Del Rosso, a prolific author and a Clinical Assistant Professor in the Department of Dermatology at the University of Nevada School of Medicine, describes an array of common lower-extremity skin conditions. His informative article offers diagnostic insights and helpful treatment recommendations as well.

At the end of this article, you’ll find a ten-question exam. Please mark your responses on the postage-paid postcard and return it to HMP Communications. This course will be posted on Podiatry Today’s Web site (www.podiatrytoday.com) roughly one month after the publication date. I hope this CE series contributes to your clinical skills.

Sincerely,

Jeff A. Hall
Editor-In-Chief
Podiatry Today

INSTRUCTIONS: Physicians may receive one continuing education contact hour (.1 CEU) by reading the article on pg. 62 and successfully answering the questions on pg. 68. Use the postage-paid card provided to submit your answers or log on to www.podiatrytoday.com and respond electronically.
ACCREDITATION: HMP Communications, LLC is approved by the Council on Podiatric Medical Education as a sponsor of continuing education in podiatric medicine.
DESIGNATION: This activity is approved for 1 continuing education contact hour or .1 CEU.
DISCLOSURE POLICY: All faculty participating in Continuing Education programs sponsored by HMP Communications, LLC are expected to disclose to the audience any real or apparent conflicts of interest related to the content of their presentation.
DISCLOSURE STATEMENTS: Dr. Del Rosso has served as a consultant and/or on the speakers bureau for several companies that are directly associated with several subject areas and medications mentioned in this article. These companies include Allergan, Bristol-Myers Squibb, Connetics, Dermik, Galderma, Glaxo-Smith Kline, Healthpoint, Janssen, Medicis, Novartis, Ortho Dermatologic and 3M Pharmaceuticals.
GRADING: Answers to the CE exam will be graded by HMP Communications, LLC. Within 60 days, you will be advised that you have passed or failed the exam. A score of 70 percent or above will comprise a passing grade. A certificate will be awarded to participants who successfully complete the exam.
TARGET AUDIENCE: Podiatrists.
RELEASE DATE: September 2002.
EXPIRATION DATE: September 30, 2003.
LEARNING OBJECTIVES: At the conclusion of this activity, participants should be able to:
• list several dermatologic disorders that often involve the lower extremities;
• describe common disorders that often result in misdiagnosis as tinea pedis or eczematous eruptions;
• outline antifungal therapy treatment regimens for the common clinical presentations of tinea pedis; and
• discuss oral antibiotic selection for superficial bacterial pyodermas affecting the lower extremities.

Sponsored by HMP Communications, LLC.

Here is a follow-up view of the same patient. Three weeks later, the eruption had cleared with twice daily application of ciclopirox 0.77% cream.

Here is an example of pitted keratolysis. Note the round and oblong pitted-appearing superficial depressions on the plantar surface of the medial heel region. The maceration, which is characteristic of hyperhidrosis, has created a white surface color (“so

Here we see juvenile plantar dermatosis. Note the fissuring and scaling of the distal plantar surface in this young patient. There is no erythema or inflammation.

Here you can see clearance of the same eruption four weeks after initiating therapy with clocortolone pivalate cream followed by dimeticone 1%- aluminum magnesium hydroxide stearate protectant, applied three times daily.

Here is plantar mocassin tinea pedis extending onto the lateral ankle region. Note the sharply demarcated margin of the eruption, with a scaly accentuated border immediately above the lateral malleolus region.

$Here is a close-up view of localized digital psoriasis involving the left large toe of a 32-year-old female. The eruption had been persistent for several months and was refractory to therapy with topical antifungal agents, a high-potency topical corticos$

Author(s):

By James Q. Del Rosso, DO, FAOCD

Dermatoses of the lower extremities are fairly common.¹ These conditions include infectious, inflammatory, vascular, neoplastic and traumatic dermatoses. Many dermatologic conditions (i.e. psoriasis, lichen planus) that exhibit the potential for widespread distribution can be prone to occur on the legs, ankles or feet in some patients. Other disorders characteristically involve the lower extremities. For example, dyshidrotic eczema and pitted keratolysis are examples of dermatoses that involve the plantar surface of the foot.
With this in mind, let’s take a closer look at these conditions and the appropriate treatment regimens for each.

Diagnosing And Managing Pitted Keratolysis
Pitted keratolysis is a superficial bacterial infection that involves the weightbearing regions of the plantar surface and usually affects both feet.² You’ll find that young adults and children are most often affected by this condition.³ Several keratinase-producing bacteria (including Corynebacterium spp, Micrococcus sedentarius and Streptomyces spp) have been implicated.^1,4

These patients often have a “soggy stratum corneum” caused by prolonged exposure of the feet to closed, moisture-impermeable shoes and sweaty socks. Superficial maceration and plantar hyperhidrosis are commonly associated features. Keep in mind that this disorder is often misdiagnosed and erroneously treated as tinea pedis.
Another plantar disorder associated with hyperhidrosis is symmetrical lividity. This entity, which predominantly affects young adult males, presents as sweaty or macerated anterior and posterior soles.^1,5 Unlike pitted keratolysis, plantar symmetrical lividity demonstrates a macular, purplish-red livedo-like appearance. However, be aware that pitted keratolysis and symmetrical lividity may coexist in the same patient.⁵
Pitted keratolysis is asymptomatic, but is often associated with malodor. The clinical features are usually always diagnostic, presenting as multiple, shallow, round or oblong, punched out-appearing depressions. The etiologic bacterial organisms are not easily cultured using standard media, but you may be able to identify them in routinely stained, formalin-fixed histologic sections of shaved stratum corneum.² Since the clinical features are so distinctive, laboratory diagnostic testing is not needed.

The primary goals of therapy for pitted keratolysis are: (1) promotion of dryness; (2) control of hyperhidrosis; (3) minimized exposure to occlusive footwear; (4) improved hygience; and (5) eradication of bacterial overgrowth.^2,4
Nightly application of aluminum chloride 20% solution is very effective. The drying effect of topical aluminum chloride may be significant enough to warrant using an emollient in the morning to prevent symptomatic irritation, chafing and fissuring. Having patients apply topical clindamycin phosphate 1% or erythromycin 2% (solution or gel) twice a day until they achieve clearance is very effective.^2-4 Alcohol-based formulations of benzoyl peroxide 6–10% can be used as a cleanser. The “leave on” gel is also effective.² It is important to inform the patient that benzoyl peroxide, specifically when it is used with a “leave on” gel, may bleach color from fabric (i.e. colored socks).
For long-term control of underlying chronic hyperhidrosis, you may emphasize intermittent use of topical aluminum chloride 20% solution, usually one to three nights per week, or topical aluminum chloride 6.25% solution, which is applied more frequently (i.e. nightly, every other night) to maintain control of pedal sweating.