nutrition. JPEN J Parenter Enteral Nutr. 1989;13:209.
correction appears in Nutr Clin Pract. 1996;11:120]. Nutr Clin Pract. 1996;11:59.
Dabney A et al. Short bowelsyndrome after trauma. Am J Surg. 2004;188:792–795.
Support: A Case-Based Core Curriculum. Dubuque, IA: Kendall/Hunt Publishing; 2001:517.
Malone AM. Supplemental zinc in wound healing: is it beneficial? Nutr Clin Pract. 2000;15:253.
study management. Am J Surg. 1967;114:393–397.
experimental observations. Ann Surg. 1966;164:622–634.
patients with severe short bowelsyndrome. Gut. 1989;30:943–949.
Ann Pharmacother. 1991;25:276–283.
catheter sepsis. Clin Nutr. 2005;24:220–223.
The accurate assessment of dermatologic conditions is primarily based
on the appearance and location of the skin lesion, plus age, sex,
symptoms, and current and past personal and family history.
Dry skin (xerosis) is a common condition that may occur alone or with a
variety of dermatologic disorders and requires appropriate treatment
depending on geographic location.
The selection of topical corticosteroid is based on the nature of the lesion
(wet vs. dry), the concentration of the corticosteroid, the nature of the
vehicle, the corticosteroid potency, the location of the lesion, and the
Topical corticosteroids can cause a variety of adverse effects and
adverse reactions that may require adjustment of therapy including
changing products or discontinuing their use.
Atopic dermatitis is a common dermatologic condition characterized by
eczematous lesions, dry skin, and intense pruritus. Most patients have a
family or personal history of other atopic diseases such as asthma and
allergic rhinitis. Atopic dermatitis is primarily treated with topical
corticosteroids and emollients.
Tables 39-3, 39-5, 39-6, 39-7,
Allergic contact dermatitis is one of the most common dermatologic
conditions seen by pharmacists. Drugs (neomycin), plants (Rhus),
chemicals, detergents, metals (nickel), and organic products (latex) are
common causes. Treatment consists of removal of the antigen and use
of topical or systemic corticosteroids.
Medications are a common cause of a variety of dermatologic disorders.
Timing relative to medication ingestion and principles of dermatologic
assessment are important to identify potential life-threatening adverse
ANATOMY AND PHYSIOLOGY OF THE SKIN
The skin is the largest organ in the body and constitutes, on average, 17% of a
person’s body weight. The skin’s thickness ranges from 3 to 5 mm. Figure 39-1
shows a cross section of the anatomy of human skin. Physiologically, the major
function of skin is to protect underlying structures from trauma, temperature
variations, mechanical penetrations, moisture, humidity, radiation, and invasion of
microorganisms. There are three layers of skin: epidermis, dermis, and subcutaneous
The major function of the epidermis is to serve as a barrier. The epidermis keeps
chemicals and other substances from penetrating into the body and prevents the loss
of water from the skin and underlying tissues.
The stratum corneum, which is composed of dead cells, provides the greatest
resistance to the percutaneous absorption of chemicals and drugs. It behaves as a
semipermeable membrane through which drugs are absorbed by passive diffusion.
Factors that can enhance drug absorption are hydration of the skin and damage to the
stratum corneum. In general, the greater the damage to the stratum corneum, the
greater is the absorption of topically applied drugs. Skin diseases affecting only the
epidermis heal without scarring.
Figure 39-1 Cross section of the anatomy of human skin.
The dermis is composed of collagen fibers and ranges in thickness from 1 to 4 mm.
The major function of the dermis is to protect the body from mechanical injury and to
support the dermal appendages (i.e., sweat and sebaceous glands, hair follicles) and
the epidermis. It also provides capillary, lymphatic, and nerve supply to the skin and
its appendages. The dermis contains large amounts of water, thus serving as a water
storage organ as well. Importantly, all but the most superficial injuries to the dermis
generally result in scarring as the wound heals.
Drugs passing through the epidermis penetrate directly into the dermis and may be
absorbed into the general circulation through the capillary network. Only small
amounts of topically applied drugs enter the dermis via the sweat glands or the
The subcutaneous layer supports the dermis and epidermis and serves as a fat storage
area. This layer helps regulate temperature, provide nutritional support, and cushion
One of the dermatologic axioms regarding therapy is particularly useful in selecting
dosage forms: “If it is wet, dry it; if it is dry, wet it.” Paradoxically, wet dressings
(e.g., Burow solution) are most useful in drying acute, inflamed lesions because they
draw out fluid as they evaporate. Ointment-type bases increase hydration to an
affected area by slowing water evaporation from the skin and are most useful for
chronic, lichenified, scaling lesions. The choice of vehicle for chronic lesions is
often based on what the patient has found to work best or is willing to use.
Frequently, patients with chronic dermatologic conditions use multiple types of
vehicles concomitantly (e.g., cream bases, which are drying because they are oil in
water emulsions) during the day, because they are cosmetically acceptable, and
ointment bases at night (greasy, but better emollients).
Acute inflammatory lesions can be characterized by vesiculation, erythema, swelling,
warmth, pruritus, oozing, or weeping. Generally, depending on the part of the body
involved, the more severe the dermatitis, the milder is the initial topical therapy
would be. For instance, cool water in the form of a wet dressing, soak, or bath is
more effective as the initial therapeutic agent than a potent topical corticosteroid
applied to a warm, erythematous, weeping dermatitis.
Subacute lesions are characterized by decreasing vesiculation and are often covered
with crusts. They still require cleaning and drying with aqueous preparations, but for
a shorter duration than with acute lesions. Chronic inflammatory lesions are
characterized by erythema, scaling, lichenification, dryness, and pruritus. There are
no absolute rules for treating chronic lesions. If the lesion is dry, an oleaginous or
occlusive base should be used.
DERMATOLOGIC DRUG DELIVERY SYSTEMS
Dermatologic formulations are available in a variety of forms: solutions, suspensions
or shake lotions, powders, lotions, emulsions, gels, creams, ointments, and aerosols.
Each dermatologic delivery vehicle has specific characteristics and uses based on
the type, relative acuteness, and location of the lesion.
Solutions provide evaporative cooling and vasoconstriction, with resultant mild
antipruritic effects. They soothe and cool inflamed skin, dry oozing lesions, soften
crusts, aid in cleaning wounds, and assist in the drainage of purulent wounds.
Aqueous solutions are most useful for acutely inflamed, oozing lesions; erosions, and
ulcers, and are often applied as wet dressings. In most instances, solutions should be
the sole therapy until the oozing or weeping subsides. If other topical medications are
applied, they will be washed away and will not provide the desired effect. The most
commonly used solutions are normal saline (0.9% NaCl) and aluminum acetate 5%
solution (Burow solution) diluted 1:10 to 1:40.
The most important component of a solution is water. Although active or inert
substances may be added to solutions, the cleansing, drying, and cooling effect of
water provides the major therapeutic benefit. Some of the products (e.g., Burow
solution) also have astringent properties that alter the skin surface and interstitial
spaces to cause contraction and wrinkling. Water penetration is reduced to minimize
edema, inflammation, and exudation. Table 39-1 lists the most commonly used
solutions. Boric acid should not be used as a topical agent because it can be
absorbed through the skin, causing systemic toxicity.
Solutions for Wet Dressings or Drying Weeping Lesions
Normalsaline 0.9% NaCl 1 tsp NaCl per pint
Silver nitrate 0.1%–0.5% 1 tsp of 50% stock
bUsed primarily for Pseudomonas aeruginosa infections.
Source: Arndt KA, Hsu JHS, eds. Manual of Dermatologic Therapies: With
Essentials of Diagnosis. 8th ed. Philadelphia, PA: Lippincott Williams & Wilkins;
Depending on the affected area and its size, a patient may soak the affected area
directly in the solution for 15 to 30 minutes 3 to 6 times per day. If larger areas are
involved or if the affected area cannot be easily soaked (e.g., a shoulder), a clean
towel or cloth soaked in the solution (lightly wrung out) is directly applied to the
lesion(s) as a wet dressing. The soaked cloth should be left in place for 5 to 10
minutes and then resoaked in the solution and reapplied. The patient may repeat this
procedure for 15 to 30 minutes 3 times daily. Solutions applied with a cloth should
have the cloth material wrapped around the lesions several times, if possible. If large
areas are involved, the patient may draw a bath, add appropriate amounts of
medications found in Table 39-1, and soak for 15 to 30 minutes 3 to 6 times/day. In
general, no more than one-third of the body should be soaked in this manner at any
time. Evaporation can concentrate solutions, potentially making them too irritating to
use. Small volumes of a 1:40 concentration of Burow solution left standing open at
room temperature after 30 to 60 minutes may yield a 1:10 solution. For this reason,
wet dressings should always be freshly prepared (i.e., within 24 hours), kept in
closed containers, and never reused. When drying the affected area after a wet
dressing has been used, care must be taken not to irritate the inflamed skin by rubbing
it with a towel; rather, the area should be patted dry gently with a soft, clean towel.
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