Xerosis and Fissures
Dry, scaly, and cracking skin, especially on the heels, can often lead to painful fissures and increase the risk of infection. Treatment begins with daily foot hygiene using a mild soap to remove dirt, sweat, and dead skin, followed by careful drying and the application of an emollient-based product. These products may contain moisturizers, humectants, lipids, and/or keratolytic agents. Emollients aid in smoothing and rehydrating the skin by reducing the epidermal water loss and replacing natural skin lipids. Products that contain lipids (e.g., lanolin, petroleum) and humectants (e.g., glycerol, propylene glycol) should be selected. However, many individuals are sensitive to lanolin-containing products and thus should use caution (Proksch, 2008).
Emollients are available as lotions, creams, or ointments. The difference in these formulations is the lipid content, with lotions containing the least and ointments the most. A formulation that best addresses the level of dryness present should be selected (Nazarko, 2009). Emollient products should be applied twice daily but not between the toes, as this increases the risk for fungal and/or bacterial infections, especially when moisture is present. Products containing perfumes or dyes should be avoided. Products such as Eucerin® Plus Intensive Repair Foot Creme or Lubriderm® Intensive Skin Repair Ointment are beneficial. A comparison of OTC and prescription products appears in the Table.
Table: Over-The-Counter (OTC) and Prescription Recommendations for Common Foot Conditions in Older Adults
If hyperkeratosis exists, a product containing urea or ammonium lactate and other alpha hydroxy acid (AHA) formulations such as LacHydrin® should be applied to the area. The urea softens hyperkeratotic skin by dissolving the intracellular matrix, resulting in the loosening of the horny layer of the skin. The AHAs have kerotolytic properties that decrease the adhesion of keratinocytes, increasing the turnover of the outer skin layer, thus leaving the skin smoother (Kockaert & Neumann, 2003). These products should be used one to two times daily for up to 3 weeks, then tapered to 1 to 3 days per week, then 1 to 2 days each week.
When fissures are present, deep cracks furrow into the dermis and are considered wounds. While the goal is to close the fissure and promote healing, this is often difficult due to the excessively thick, hyperkeratotic, and dry skin that surrounds the fissure. To treat the thick and dry skin, the area should be thoroughly cleansed with mild soap and water, then patted dry. A keratolytic product such as Kerasal® can be applied to reduce skin thickness. Prescription-strength keratolytic agents such as Carmol® 40% or Keralac® 50% that contain higher concentrations of urea can be used for stubborn skin thickness. Products should be applied once or twice daily to the affected area until the thickened skin is removed. In addition, treatment is often accompanied by mechanical debridement of the area with a somewhat course file of 100 grit so the agent can penetrate the thickened skin. Filing the skin frequently with minimal pressure can remove much of the thickened skin, but this takes time. After the thickened skin is removed, the fissure should be treated with an application of skin adhesives or sealants. Some of these OTC products include Nu Skin® or BAND-AID® Single Step™ Liquid Bandage over which cloth tape or even Steri-Strips® can be applied to keep the fissure closed. Prescription-strength skin adhesives such as Dermabond® can be applied to fill the fissure. For very deep, bleeding, or infected fissures, a health care provider should be consulted.
Fungal infections of the feet frequently target the nails (onychomycosis), can be difficult to treat, and can cause functional impairment when shoes or slippers rub against thickened and loosened toenails. No less important are fungal infections of the skin (tinea pedis, or athlete’s foot). However, skin infection is more sensitive to topical treatment than onychomycosis due to the penetrable nature of the skin.
Onychomycosis. Onychomycosis is prevalent in almost 15% of the U.S. population and is thought to be much higher in older adults. It is the most common nail disorder; 80% of all cases affect the feet compared with the fingers (Jacobson & Zajac, 2008). The toenail is susceptible to fungus due to its constant bombardment of moisture and exposure to unclean environments. The fungus causes mild to severe dystrophic changes in nail color (brown, yellow, white specks), texture (thick, brittle, flaky, crumbly), and integrity (loosened from the nail bed) (Figure 3). In addition to aging, other risk factors include immunocompromised status, trauma to the nail, diabetes, and skin problems such as psoriasis. Smoking and the presence of tinea pedis have been associated with onychomycosis. Rarely does the infection cause pain, except when the nail is extremely thick, long, and rubs against a shoe or sheet. Dermatophytes such as Trichophyton rubrum are the most common culprits, whereas yeasts and molds are the least.
Figure 3. Onychomycosis, Nail Fungus that Causes Changes in Nail Color, Texture, and Integrity.Photo Credit: Teresa J. Kelechi, PhD, RN, GCNS-BC, CWCN.
Topical approaches to treat onychomycosis depend on numerous factors such as severity, age of the patient, and concomitant illnesses. Cost of the medications and whether the aim of treatment is to eradicate the fungus or improve nail appearance all influence treatment approaches. Eradicating the fungus and preventing its return require longer treatment commitments and full patient adherence to therapy. An important consideration to make when choosing between treatment options (topical, systemic, or both) is the potential for adverse events. Severe events are extremely rare with topical treatments, but they can produce rash, redness, burning, or itching sensations of the skin.
Many older adults are unable to tolerate or afford oral medications and therefore many turn to OTC products. For example, tea tree oil has been advanced as a treatment for nail infection. However, limited evidence supports its use for curing onychomycosis or tinea pedis. Findings from one small clinical trial found it was ineffective (Satchell, Saurajen, Bell, & Barnetson, 2002). Unfortunately, many of these OTC products have a low efficacy profile, and patients should be advised to use caution when applying any kind of OTC treatment.
The limited body of research for topical prescription medications indicates mixed results in cure rates. For the best outcomes, topical treatments such as creams, gels, and lacquers should be applied to nails where only the nail plate is involved, not the matrix. The matrix is the area of tissue located distal to and under the bottom of the nail plate where the cells “grow” the nail plate. Treating the matrix topically is difficult because most products cannot penetrate to the depth needed to reach the cells. It is also important to use topical agents in early distal nail disease and when there are few nails involved (Baran, Hay, & Garduno, 2008a).
While prescription topical agents have better efficacy than OTC preparations, monotherapy—the use of one kind of topical agent by itself—has a suboptimal cure rate. Recent evidence shows that a common topical monotherapy delivered through a transungual drug delivery system (TDDS), or colorless nail lacquer, is a step forward from previous ineffective topical agents (Baran et al., 2008b). Two common TDDS are ciclopirox olamine 8% (Penlac®) and amorolfine 5% (Loceryl®). Ciclopirox is applied to the nail daily, each layer on top of the other, without removal. The layers are removed every 7 days with nail polish remover or alcohol, and the daily regimen is continued until the nail is clear of infection, usually 6 to 9 months. Unfortunately, cure rates after approximately 1 year are estimated between 30% and 40%.
There is general consensus that topical monotherapy should be used where less than 50% of the nail surface is affected, without matrix involvement. In cases where the nail is so affected that the topical treatment cannot penetrate the nail, such as a loosened and extremely thick nail, chemical or mechanical thinning or removal of the nail should be considered. The most efficacious approach to treating onychomycosis is using both oral and topical therapies when there is greater than 50% of the nail plate involved.
It is important to advise older patients who are using topical agents to avoid discontinuing the treatment as soon as the nails look normal. The fungal infection tends to rapidly reoccur into a full-blown infection. Patients should be reminded to continue the treatment as prescribed, as it is important for the drug to remain in the nail tissue for some time after resolution of symptoms.
Tinea Pedis. Fungal infections of pedal skin tend to target the skin where there is contact with the shoe or between the toes. Interdigit infections involve the toe web spaces, appear whitish, and can have cracks and peel. Pedal skin infections can mimic dry flaky skin; however, there is often an element of peeling and redness. Sometimes a splotchy, rash-like appearance and severe itching are present. Inflammation and open draining areas are the most severe form. Topical treatments vary widely. Topical therapy to treat tinea pedis has a much better outcome compared with topical treatment for onychomycosis (Korting, Kiencke, Nelles, & Rychlik, 2007). The risk factors for developing tinea pedis, in addition to those noted for onychomycosis, include chronic exposure to damp, moist environments such as shoes or communal areas such as showers. The best approach to managing tinea pedis lies in its prevention by reducing dampness and exposure to communal environments. Wearing socks that wick moisture from the skin, frequently changing shoes, and limited application of moisturizers to the areas between the toes are helpful.
In the presence of tinea pedis, topical therapies can be effective in reducing peeling skin, redness, itchiness, and in severe cases, split, cracked and bleeding skin or severely macerated toe web spaces. A recent meta-analysis of randomized clinical trials (Crawford & Hollis, 2007) suggests that the best results for the treatment of tinea pedis were observed with the use of allylamines such as terbinafine (Lamisil®), naftifine (Naftin®), and butenafine (Mentax®) for 1 week. Azoles such as miconazole (Lotrimin®) and econazole (Spectazole®) are also very effective but should be applied to the skin for 4 weeks. For interdigit tinea, the application of ciclopirox 0.77% gel, applied once or twice daily, is effective and safe (Gupta, Skinner, & Cooper, 2003).
Mounting evidence supports the application of a single-dose film-forming solution to infected skin (de Chauvin, Viguié-Vallanet, Kienzler, & Larnier, 2008). For example, terbinafine 1% has been found to be highly effective and remains in the skin for up to 13 days (Schäfer-Korting, Schoellmann, & Korting, 2008). This novel approach is a significant advancement that enhances adherence and is convenient.
Topical therapies for skin infections are readily available, generally easy to apply, and have low adverse event profiles. Proper hygiene, keeping feet dry, and wearing socks that wick moisture (synthetic fabrics) are important adjuvants when working with older adults. When adults’ backs do not bend as easily and eyesight is failing, it is often difficult for them to reach between the toes and visually inspect the skin for infection. Thus, infections often go unnoticed. Older patients should be advised to seek treatment early when symptoms first appear rather than waiting for a full-blown skin infection, which can be harder to resolve with topical therapy.