Topical Therapy and Topical Corticosteroids

Topical Therapy

A wide variety of topical medications are available for treating cutaneous disease (see Formulary). Specific medications are covered in detail in the appropriate chapters, and the basic principles of topical treatment are discussed here.

The skin is an important barrier that must be maintained to function properly. Any insult that removes water, lipids, or protein from the epidermis alters the integrity of this barrier and compromises its function. Restoration of the normal epidermal barrier is accomplished with the use of mild soaps and emollient creams and lotions. There is an old and often-repeated rule: “If it is dry, wet it; if it is wet, dry it.”

Dry Diseases

Dry skin or dry cutaneous lesions have lost water and, in many instances, the epidermal lipids and proteins that help contain epidermal moisture. These substances are replaced with emollient creams and lotions.

Wet Diseases

Exudative inflammatory diseases leak serum that leaches the complex lipids and proteins from the epidermis. A wet lesion is managed with wet compresses that suppress inflammation and debride crust and serum. Repeated cycles of wetting and drying eventually make the lesion dry. Excessive use of wet dressings causes severe drying and chapping. Once the wet phase of the disease has been controlled, the lipids and proteins must be restored with the use of emollient creams and lotions, and wet compressing should stop.

Emollient Creams and Lotions

Emollient creams and lotions restore water and lipids to the epidermis (see Formulary). Preparations that contain urea (e.g., Carmol 10, 20, 40; Vanamide) or lactic acid (e.g., Lac-Hydrin, AmLactin) have special lubricating properties and may be the most effective. Creams are thicker and more lubricating than lotions; petroleum jelly and mineral oil contain no water.

Lubricating creams and lotions are most effective if applied to moist skin. After bathing is an ideal time to apply moisturizers. Wet the skin and pat it dry, then immediately apply the moisturizer. Emollients should be applied as frequently as necessary to keep the skin soft. Chemicals such as menthol and phenol (e.g., Sarna lotion) are added to lubricating lotions to control pruritus (see Formulary).

Severe Dry Skin (Xerosis)

Dry skin is more severe in the winter months when the humidity is low. “Winter itch” most commonly affects the hands and lower legs. Initially the skin is rough and covered with fine white scales; later, thicker tan or brown scales may appear. The most severely affected skin may be crisscrossed with shallow red fissures. Dry skin may itch or burn. Numerous creams and lotions are available to treat dry skin. They are all effective.

Wet Dressings

Wet dressings, also called compresses, are a valuable aid in the treatment of exudative (wet) skin diseases ( Box 2.1 ). Their importance in topical therapy cannot be overstated.

Box 2.1

Diseases Treated With Wet Compresses

Acute eczematous inflammation (poison ivy)
Bullous impetigo
Eczematous inflammation with secondary infection (pustules)
Herpes simplex and herpes zoster (vesicular lesions)
Infected exudative lesions of any type
Insect bites
Intertrigo (groin or under breasts)
Nummular eczema (exudative lesions)
Stasis dermatitis (exudative lesions)
Stasis ulcers
Sunburn (blistering stage)
Tinea pedis (vesicular stage or macerated web infections)

The technique for wet compress preparation and application is described in the following list.

1
Obtain a clean, soft cloth such as bedsheeting or shirt material. The cloth need not be new or sterilized. Compress material must be washed at least once daily if it is to be used repeatedly.
2
Fold the cloth so there are at least four to eight layers and cut it to fit an area slightly larger than the area to be treated ( Fig. 2.1 ).
3
Wet the folded dressings by immersing them in the solution, and wring them out until they are sopping wet (neither running nor just damp).
4
Place the wet compresses on the affected area. Do not pour solution on a wet dressing to keep it wet because this practice increases the concentration of the solution and may cause irritation. Remove the compress and replace it with a new one.
5
Dressings are left in place for 30 minutes to 1 hour. Dressings may be used two to four times a day or continuously. Discontinue the use of wet compresses when the skin becomes dry. Excessive drying causes cracking and fissures.

Wet compresses provide the following benefits:

Antibacterial action: Aluminum acetate, acetic acid, or silver nitrate may be added to the water to provide an antibacterial effect ( Table 2.1 ).

TABLE 2.1

Wet Dressing Solutions

Solution	Preparation	Indications
Water	Tap water does not have to be sterilized.	Poison ivy, sunburn, any noninfected exudative or inflamed process
Burow's solution (aluminum acetate) Domeboro astringent powder packets Effervescent tablets	Dissolve 1, 2, or 3 packets of Domeboro powder in 16 ounces of water.	Mildly antiseptic; for acute inflammation, poison ivy, insect bites, athlete's foot
Silver nitrate 0.1%–0.5% (prepared by some pharmacists and some hospitals)	Supplied as a 50% aqueous solution; stains skin dark brown and stains metal black.	Bactericidal: for exudative infected lesions (e.g., stasis ulcers and stasis dermatitis)
Acetic acid 1%–2.5%	Vinegar is 5% acetic acid. Make a 1% solution by adding cup of vinegar (white or brown) to 1 pint of water.	Bactericidal: for certain Gram- negative bacteria (e.g., Pseudomonas aeruginosa ), otitis externa, Pseudomonas intertrigo

Wound debridement: A wet compress macerates vesicles and crust, helping to debride these materials when the compress is removed.
Inflammation suppression: Compresses have a strong antiinflammatory effect. The evaporative cooling causes constriction of superficial cutaneous vessels, thereby decreasing erythema and the production of serum. Wet compresses control acute inflammatory processes, such as acute poison ivy, faster than either topically applied or orally administered corticosteroids.
Drying: Wet dressings cause the skin to become dry. Wetting something to make it dry seems paradoxical, but the effects of repeated cycles of wetting and drying are observed in lip chapping, caused by lip licking; irritant hand dermatitis, caused by repeated washing; and soggy sock syndrome in children, caused by perspiration.

The temperature of the compress solution should be cool when an antiinflammatory effect is desired and tepid when the purpose is to debride an infected, crusted lesion. Covering a wet compress with a towel or a piece of plastic inhibits evaporation, promotes maceration, and increases skin temperature, which facilitates bacterial growth.

Topical Corticosteroids

Topical corticosteroids are a powerful tool for treating skin disease. Understanding the correct use of these agents will result in the successful management of a variety of skin problems. Many products are available, but all have basically the same antiinflammatory properties, differing only in strength, base, and price.

Strength

Potency (Groups I Through VII)

The antiinflammatory properties of topical corticosteroids result in part from their ability to induce vasoconstriction of the small blood vessels in the upper dermis. This property is used in an assay procedure to determine the strength of each new product. These products are subsequently tabulated in seven groups, with group I the strongest and group VII the weakest (see the Formulary and the inside front matter of this book). The treatment sections of this book recommend topical steroids by group number rather than by generic or brand name because the agents in each group are essentially equivalent in strength.

Lower concentrations of some brands may have the same effect in vasoconstrictor assays as much higher concentrations of the same product. One study showed that there was no difference in vasoconstriction between Kenalog 0.025%, 0.1%, and 0.5% creams.

Choosing the Appropriate Strength

Guidelines for choosing the appropriate strength and brand of topical steroid are presented in Table 2.2 and Fig. 2.2 . The best results are obtained when preparations of adequate strength are used for a specified length of time. Weaker, “safer” strengths often fail to provide adequate control. Patients who do not respond after 1 to 4 weeks of treatment should be reevaluated.

TABLE 2.2

Suggested Strength of Topical Steroids to Initiate Treatment *

Groups I–II	Groups III–V	Groups VI–VII
Psoriasis	Atopic dermatitis	Dermatitis (eyelids)
Lichen planus	Nummular eczema	Dermatitis (diaper area)
Discoid lupus ^†	Asteatotic eczema	Mild dermatitis (face)
Severe hand eczema	Stasis dermatitis	Mild anal inflammation
Poison ivy (severe)	Seborrheic dermatitis	Mild intertrigo
Lichen simplex chronicus	Lichen sclerosus et atrophicus (vulva)
Hyperkeratotic eczema	Intertrigo (brief course)
Chapped feet	Tinea (brief course to control inflammation)
Lichen sclerosus et atrophicus (skin)	Scabies (after scabicide)
Alopecia areata	Intertrigo (severe cases)
Nummular eczema (severe)	Anal inflammation (severe cases)
Atopic dermatitis (resistant adult cases)	Severe dermatitis (face)

* Stop treatment, change to less potent agent, or use intermittent treatment once inflammation is controlled.

† Use on the face may be justified.

Megapotent Topical Steroids (Group I)

Clobetasol propionate, halobetasol propionate, betamethasone dipropionate, and diflorasone diacetate are the most potent topical steroids available. Clobetasol and halobetasol are the most potent and betamethasone and diflorasone are equipotent.

In general, no more than 45 to 60 grams (g) of cream or ointment should be used each week ( Table 2.3 ). Side effects are minimized and efficacy increased when medication is applied once or twice daily for 2 weeks followed by 1 week of rest. This cyclic schedule (pulse dosing) is continued until resolution occurs. Intermittent dosing (e.g., once or twice a week) can lead to a prolonged remission of psoriasis if used after initial clearing. Alternatively, intermittent use of a weaker topical steroid can be used for maintenance. Diflorasone can be used with plastic dressing occlusion; clobetasol, halobetasol, and betamethasone should not be used with occlusive dressings.

TABLE 2.3

Restriction on the Use of Group I Topical Steroids *

	Length of Therapy	Grams Per Week	Use Under Occlusion
Clobetasol propionate	14 days	60	No
Clobetasol scalp solution	14 days	50 mL	No
Clobetasol foam	14 days	50	No
Halobetasol propionate	14 days	60	No
Betamethasone dipropionate	Unrestricted	45	No
Diflorasone diacetate	Unrestricted	Unrestricted	Unrestricted

* Restrictions are listed in the package inserts.

Patients must be monitored carefully. Side effects such as skin atrophy and adrenal suppression are a real possibility, especially with unsupervised use of these medications. Refills should be strictly limited. Add the warning “Not to be applied to face, axillae and groin” to prescriptions for treatment of other areas. Explain that prolonged use causes a poststeroid flare of erythema and papules on the face and atrophy in the axillae and groin.

Concentration

The concentration of steroid listed on the tube cannot be used to compare its strength with other steroids. Some steroids are much more powerful than others and need be present only in small concentrations to produce the maximum effect. Nevertheless, it is difficult to convince some patients that clobetasol cream 0.05% (group I) is more potent than hydrocortisone 1% (group VII).

It is unnecessary to learn many steroid brand names. Familiarity with one preparation from groups II, V, and VII gives you the ability to safely and effectively treat any steroid-responsive skin disease. Most of the topical steroids are fluorinated (i.e., a fluorine atom has been added to the hydrocortisone molecule). Fluorination increases potency and the possibility of side effects. Products such as hydrocortisone valerate cream have increased potency without fluorination; however, side effects are possible with this midpotency steroid.

Compounding

Avoid having the pharmacist prepare or dilute topical steroid creams. The active ingredient may not be dispersed uniformly, resulting in a cream of variable strength. The cost of pharmacist preparation is generally higher because of the additional labor required. High-quality steroid creams, such as triamcinolone acetonide, are available in large quantities at a low cost.

Generic Versus Brand Names

Many generic topical steroid formulations are available (e.g., clobetasol propionate, betamethasone valerate, betamethasone dipropionate, fluocinolone acetonide, fluocinonide, hydrocortisone, and triamcinolone acetonide). In many states, generic substitutions by the pharmacist are allowed unless the physician writes “no substitution.” Vasoconstrictor assays have shown large differences in the activity of generic formulations compared with brand-name equivalents: many are inferior, a few are equivalent, and a few are more potent than brand-name equivalents. Many generic topical steroids have vehicles with different ingredients (e.g., preservatives) than brand-name equivalents.

Vehicle

The vehicle, or base, is the substance in which the active ingredient is dispersed. The base determines the rate at which the active ingredient is absorbed through the skin. Components of some bases may cause irritation or allergy.

Creams

The cream base is a mixture of several different organic chemicals (oils) and water, and it usually contains a preservative. Creams have the following characteristics:

White color and somewhat greasy texture
Components that may cause irritation, stinging, and allergy
High versatility (i.e., may be used in nearly any area); therefore creams are the base most often prescribed
Possible drying effect with continued use; therefore best for acute exudative inflammation
Most useful for intertriginous areas (e.g., groin, rectal area, and axilla)

Ointments

The ointment base contains a limited number of organic compounds consisting primarily of greases such as petroleum jelly, with little or no water. Many ointments are preservative-free. Ointments have the following characteristics:

Translucent (look like petroleum jelly)
Greasy feeling that persists on skin surface
More lubrication, thus desirable for drier lesions
Greater penetration of medicine than creams and therefore enhanced potency (see inside front matter; triamcinolone cream in group V and triamcinolone ointment in group IV)
Too occlusive for acute (exudative) eczematous inflammation or for use in intertriginous areas, such as the groin

Gels

Gels are greaseless mixtures of propylene glycol and water; some also contain alcohol. Gels have the following characteristics:

A clear base, sometimes with a jelly-like consistency
Useful for acute exudative inflammation, such as poison ivy, and in scalp areas where other vehicles mat the hair

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