46 Approach to the Patient with a Skin Disorder 283progestin such as norgestral, desonorgestrel, or norethisterone results

in effective contraception, suggesting that a male contraceptive may

be forthcoming.

FURTHER READING

ABMA JC et al and the National Center for Health Statistics: Fertility, familyplanning, and women’s health: New data from the 1995 Survey of FamilyGrowth. Vital Health Stat 23, no. 10

ANDERSON RA et al: Male contraception. Endocr Rev 23:735, 2002GUZIK DS et al: Sperm morphology, motility and concentration in fertile and

infertile men. N Engl J Med 345:1388, 2001

KURODA-KAWAGUCHI T et al: The AZFc region of the Y chromosome fea-tures massive palindromes and uniform recurrent deletions in infertile men.Nat Genet 29:279, 2001

MARCHBANKS PA et al. Oral contraceptives and the risk of breast cancer. NEngl J Med 346:2025, 2002

TRUSSELL J, VAUGHAN B: Contraceptive failure, method-related discontinu-ation and resumption of use: Results from the 1995 National Survey ofFamily Growth. Fam Plan Perspect 31:64, 1999

Section 9 Alterations in the Skin

46APPROACH TO THE PATIENT WITH A SKIN DISORDERThomas J. Lawley, Kim B. Yancey

FIGURE 46-2 Nevi are benign proliferations of nevomelanocytes characterized byregularly shaped hyperpigmented macules or papules of a uniform color.

FIGURE 46-1 Superficial spreading melanoma is the most common type of malignantmelanoma and demonstrates color variegation (black, blue, brown, pink, and white)and irregular borders.

TABLE 46-1 Descriptions of Primary Skin Lesions

Macule: A flat, colored lesion, ,2 cm in diameter, not raised above thesurface of the surrounding skin. A “freckle,” or ephelid, is a prototypepigmented macule.

Patch: A large (.2 cm), flat lesion with a color different from the surround-ing skin. This differs from a macule only in size.

Papule: A small, solid lesion, ,0.5 cm in diameter, raised above the surfaceof the surrounding skin and hence palpable (e.g., a closed comedone, orwhitehead, in acne).

Nodule: A larger (0.5–5.0 cm), firm lesion raised above the surface of thesurrounding skin. This differs from a papule only in size (e.g., dermalnevus).

Tumor: A solid, raised growth .5 cm in diameter.Plaque: A large (.1 cm), flat-topped, raised lesion; edges may either be

distinct (e.g., in psoriasis) or gradually blend with surrounding skin (e.g.,in eczematous dermatitis).

Vesicle: A small, fluid-filled lesion, ,0.5 cm in diameter, raised above theplane of surrounding skin. Fluid is often visible, and the lesions are oftentranslucent [e.g., vesicles in allergic contact dermatitis caused by Toxi-

codendron (poison ivy)].Pustule: A vesicle filled with leukocytes. Note: The presence of pustules

does not necessarily signify the existence of an infection.Bulla: A fluid-filled, raised, often translucent lesion .0.5 cm in diameter.Cyst: A soft, raised, encapsulated lesion filled with semisolid or liquid

contents.Wheal: A raised, erythematous papule or plaque, usually representing short-

lived dermal edema.Telangiectasia: Dilated, superficial blood vessels.

The challenge of examining the skin lies in distinguishing normal from

abnormal, significant findings from trivial ones, and in integrating per-

tinent signs and symptoms into an appropriate differential diagnosis.

The fact that the largest organ in the body is visible is both an advan-

tage and a disadvantage to those who examine it. It is advantageous

because no special instrumentation is necessary and because the skin

can be biopsied with little morbidity. However, the casual observer

can be misled by a variety of stimuli and overlook important, subtle

signs of skin or systemic disease. For instance, the sometimes minor

differences in color and shape that distinguish a malignant melanoma

(Fig. 46-1) from a benign pigmented nevus (Fig. 46-2) can be difficult

to recognize. To aid in the interpretation of skin lesions, a variety of

descriptive terms have been developed to characterize cutaneous le-

sions (Tables 46-1 and 46-2 and Fig. 46-3) and to formulate a differ-

ential diagnosis (Table 46-3). For instance, the finding of large num-

bers of scaling papules, usually indicative of a primary skin disease,

places the patient in a different diagnostic category than would hem-

orrhagic papules, which may indicate vasculitis or sepsis (Figs. 46-4

and 46-5, respectively). It is important to differentiate primary skin

lesions from secondary skin changes. If the examiner focuses on linear

erosions overlying an area of erythema and scaling, he or she may

incorrectly assume that the erosion is the primary lesion and the red-

ness and scale are secondary, while the correct interpretation would

be that the patient has a pruritic eczematous dermatitis with erosions

caused by scratching.

APPROACH TO THE PATIENT

In examining the skin it is usually advisable to assess the patient

before taking an extensive history. This way, the entire cutaneous

surface is sure to be evaluated, and objective findings can be in-

tegrated with relevant historic data. Four basic features of any cu-

taneous lesion must be noted and considered in the examination of

Part II Cardinal Manifestations and Presentation of Diseases284

TABLE 46-2 Common Dermatologic Terms

Lichenification: A distinctive thickening of the skin that is characterizedby accentuated skin-fold markings and that feels thick on palpation.

Crust: Dried exudate of body fluids that may be either yellow (serous ex-udate) or red (hemorrhagic exudate).

Milia: Small, firm, white papules that are filled with keratin (and may inpart resemble pustules).

Erosion: Loss of epidermis without an associated loss of dermis.Ulcer: Loss of epidermis and at least a portion of the underlying dermis.Excoriations: Linear, angular erosions that may be covered by crust and

are caused by scratching.Atrophy: An acquired loss of substance. In the skin, this may appear as a

depression with intact epidermis (i.e., loss of dermal or subcutaneoustissue) or as sites of shiny, delicate, wrinkled lesions (i.e., epidermalatrophy).

Scar: A change in the skin secondary to trauma or inflammation. Sites maybe erythematous, hypopigmented, or hypertrophic depending on their ageor character. Sites on hair-bearing areas may be characterized by destruc-tion of hair follicles.

Pruritus: A sensation that elicits the desire to scratch. Pruritus is often thepredominant symptom of inflammatory skin diseases (e.g., atopic der-matitis, allergic contact dermatitis); it is also commonly associated withxerosis and aged skin. Systemic conditions that can be associated withpruritus include chronic renal disease, cholestasis, pregnancy, malig-nancy, polycythemia vera, and delusions of parasitosis.

FIGURE 46-4 Palpable purpuric papules onthe lower legs are seen in this patient withcutaneous small vessel vasculitis. (Courtesy ofRobert Swerlick, MD.)

bacRed

bBlue

aBrown

Mac

ule

Papule

Nod

ule

Plaqu

e

Vesicle

Bulla

FIGURE 46-3 A schematic representation of several common primary skin lesions(see Table 46-1).

FIGURE 46-5 Fulminant meningococcemia with extensive angular purpuric patches.(Courtesy of Stephen E. Gellis, MD.)

skin: the distribution of the eruption, the type(s) of primary lesion,

the shape of individual lesions, and the arrangement of the lesions.

In the initial examination it is important that the patient be disrobed

as completely as possible. This will minimize chances of missing

important individual skin lesions and make it possible to assess the

distribution of the eruption accurately. The patient should first be

viewed from a distance of about 1.5 to 2 m (4 to 6 ft) so that the

general character of the skin and the distribution of lesions can be

evaluated. Indeed, distribution of lesions often correlates highly

with diagnosis (Fig. 46-6). For example, a hospitalized patient with

a generalized erythematous exanthem is more likely to have a drug

eruption than is a patient with a similar rash limited to the sun-

exposed portions of the face. The presence or absence of lesions

on mucosal surfaces should also be determined. Once the distri-

bution of the lesions has been established, the nature of the primary

lesion must be determined. Thus, when lesions are distributed on

elbows, knees, and scalp, the most likely possibility based solely

on distribution is psoriasis or dermatitis herpetiformis (Figs. 46-7

and 46-8, respectively). The primary lesion in psoriasis is a scaly

papule that soon forms erythematous plaques covered with a white

scale, whereas that of dermatitis herpetiformis is an urticarial pap-

ule that quickly becomes a small vesicle. In this manner, identifi-

cation of the primary lesion directs the examiner toward the proper

diagnosis. Secondary changes in skin can also be quite helpful. For

example, scale represents excessive epidermis, while crust is the

result of a discontinuous epithelial cell layer. Palpation of skin

lesions can also yield insight into the character of an eruption. Thus

red papules on the lower extremities that blanch with pressure can

be a manifestation of many different diseases, but hemorrhagic red

papules that do not blanch with pressure indicate palpable purpura

characteristic of necrotizing vasculitis (Fig. 46-4).

The shape of lesions is also an important feature. Flat, round,

erythematous papules and plaques are common in many cutaneous

diseases. However, target-shaped lesions that consist in part of er-

ythematous plaques are specific for erythema multiforme (Fig. 46-

9). In the same way, the arrangement of individual lesions is im-

portant. Erythematous papules and vesicles can occur in many

conditions, but their arrangement in a specific linear array suggests

an external etiology such as allergic contact (Fig. 46-10) or primary

TABLE 46-3 Selected Common Dermatologic Conditions

Diagnosis

Common

Distribution Usual Morphology

Acne vulgaris Face, upper back Open and closed comedones,erythematous papules,pustules, cysts

Rosacea Blush area ofcheeks, nose,forehead, chin

Erythema, telangiectasias,papules, pustules

Seborrheicdermatitis

Scalp, eyebrows,perinasal areas

Erythema with greasy yellow-brown scale

Atopic dermatitis Antecubital andpopliteal fossae;may bewidespread

Patches and plaques oferythema, scaling, andlichenification; pruritus

Stasis dermatitis Ankles, lower legs Patches of erythema andscaling on background ofhyperpigmentationassociated with signs ofvenous insufficiency

Dyshidroticeczema

Palms, soles, sidesof fingers and toes

Deep vesicles

Allergic contactdermatitis

Anywhere Localized erythema, vesicles,scale, and pruritus (e.g.,fingers, earlobes—nickel;dorsal aspect of foot—shoe; exposed surfaces—poison ivy)

Psoriasis Elbows, knees,scalp, lower back,fingernails (maybe generalized)

Papules and plaques coveredwith silvery scale; nailshave pits

Lichen planus Wrists, ankles,mouth (may bewidespread)

Violaceous flat-toppedpapules and plaques

Keratosis pilaris Extensor surfaces ofarms and thighs,buttocks

Keratotic follicular papuleswith surrounding erythema

Melasma Forehead, cheeks,temples, upper lip

Tan to brown patches

Vitiligo Periorificial, trunk,extensor surfacesof extremities,flexor wrists,axillae

Chalk-white macules

Actinic keratosis Sun-exposed areas Skin-colored or red-brownmacule or papule with dry,rough, adherent scale

Basal cellcarcinoma

Face Papule with pearly,telangiectatic border onsun-damaged skin

Squamous cellcarcinoma

Face, especiallylower lip, ears

Indurated and possiblyhyperkeratotic lesions oftenshowing ulceration and/orcrusting

Diagnosis

Common

Distribution Usual Morphology

Seborrheickeratosis

Trunk, face Brown plaques with adherent,greasy scale; “stuck on”appearance

Folliculitis Any hair-bearingarea

Follicular pustules

Impetigo Anywhere Papules, vesicles, pustules,often with honey-coloredcrusts

Herpes simplex Lips, genitalia Grouped vesicles progressingto crusted erosions

Herpes zoster Dermatomal, usuallytrunk but may beanywhere

Vesicles limited to adermatome (often painful)

Varicella Face, trunk, relativesparing ofextremities

Lesions arise in crops andquickly progress fromerythematous macules topapules to vesicles topustules to crusts

Pityriasis rosea Trunk (Christmastree pattern);herald patchfollowed bymultiple smallerlesions

Symmetric erythematouspatches with a collarette ofscale

Tinea versicolor Chest, back,abdomen,proximalextremities

Scaly hyper- orhypopigmented macules

Candidiasis Groin, beneathbreasts, vagina,oral cavity

Erythematous maceratedareas with satellite pustules;white, friable patches onmucous membranes

Dermatophytosis Feet, groin, beard,or scalp

Varies with site, (e.g., tineacorporis—scaly annularpatch)

Scabies Groin, axillae,between fingersand toes, beneathbreasts

Excoriated papules, burrows,pruritus

Insect bites Anywhere Erythematous papules withcentral puncta

Cherry angioma Trunk Red, blood-filled papulesKeloid Anywhere (site of

previous injury)Firm tumor, pink, purple, or

brownDermatofibroma Anywhere Firm red to brown nodule that

shows dimpling ofoverlying skin with lateralcompression

Acrochordons(skin tags)

Groin, axilla, neck Fleshy papules

Urticaria Anywhere Wheals, sometimes withsurrounding flare; pruritus

Transient acantho-lytic dermatosis

Trunk, especiallyanterior chest

Erythematous papules

Xerosis Extensorextremities,especially legs

Dry, erythematous, scalingpatches; pruritus

irritant dermatitis. In contrast, lesions with a generalized arrange-

ment are common and suggest a systemic etiology.

As in other branches of medicine, a complete history should be

obtained to emphasize the following features:

1. Evolution of lesions

a. Site of onset

b. Manner in which the eruption progressed or spread

c. Duration

d. Periods of resolution or improvement in chronic eruptions

2. Symptoms associated with the eruption

a. Itching, burning, pain, numbness

b. What, if anything, has relieved symptoms

c. Time of day when symptoms are most severe

3. Current or recent medications (prescribed as well as over-the-

counter)

4. Associated systemic symptoms (e.g., malaise, fever, arthral-

gias)

5. Ongoing or previous illnesses

6. History of allergies

7. Presence of photosensitivity

8. Review of systems

DIAGNOSTIC TECHNIQUES Many skin diseases can be diagnosed on gross

clinical appearance, but sometimes relatively simple diagnostic pro-

cedures can yield valuable information. In most instances, they can be

performed at the bedside with a minimum of equipment.

Actinic

keratoses

Basal cell

carcinoma

Contact

dermatitis

Skin tags

Acne vulgaris

Perleche

Seborrheic

dermatitis

Acne rosacea

Xanthelasma

Seborrheic

dermatitis

Melasma

Seborrheic

dermatitis

C Herpes labialis

Leukoplakia

Squamous cell

carcinoma

Oral hairy

leukoplakia

Aphthous

stomatitis

Geographic

tongue

Lichen planus

D

Psoriasis

Acne

vulgaris

Pityriasis

rosea

Lichen

planus

Perianal lesions

Hemorrhoids

Condyloma acuminata Herpes simplex

Dermatitis

Vitiligo

Atopic

dermatitis

Hand eczema

Verruca plana

Tinea pedis

Lichen simplex

chronicus

Asteatotic

eczema

Verrucae vulgaris

Keratosis

pilaris

Skin tags

Seborrheic

keratoses

Senile

angioma

Atopic

dermatitis

Tinea orCandidacruris

Actinic

keratoses

Psoriasis

Dermatofibroma

Stasis ulcer

Stasis dermatitis

Tinea pedis

Dyshidrotic

eczema

Epidermal

inclusion

cyst

Herpes

zoster

Psoriasis

Psoriasis

Folliculitis

A B

FIGURE 46-6 A–D. The distribution of some common dermatologic diseases and lesions.

FIGURE 46-7 Psoriasis is characterized by small and large erythematous plaques with

adherent silvery scale.

Skin Biopsy A skin biopsy is a straightforward minor surgical proce-

dure; however, it is important to biopsy a lesion that is most likely to

yield diagnostic findings. This decision may require expertise in skin

diseases and knowledge of superficial anatomic structures in selected

areas of the body. In this procedure, a small area of skin is anesthetized

with 1% lidocaine with or without epinephrine. The skin lesion in

question can be excised with a scalpel or removed by punch biopsy.

In the latter technique, a punch is pressed against the surface of the

skin and rotated with downward pressure until it penetrates to the

subcutaneous tissue. The circular biopsy is then lifted with forceps,

and the bottom is cut with iris scissors. Biopsy sites may or may not

need suture closure, depending on size and location.

KOH Preparation A potassium hydroxide (KOH) preparation is per-

formed on scaling skin lesions where a fungal etiology is a possibility.

The edge of such a lesion is scraped gently with a scalpel blade, and

the removed scale is collected on a glass microscope slide and treated

with 1 to 2 drops of a solution of 10 to 20% KOH. KOH dissolves

keratin and allows easier visualization of fungal elements. Brief heat-

ing of the slide accelerates dissolution of keratin. When the preparation

46 Approach to the Patient with a Skin Disorder 287

FIGURE 46-8 Dermatitis herpetiformis manifested by pruritic, grouped vesicles in atypical location. The vesicles are often excoriated and may occur on knees, buttocks,and posterior scalp.

A

B

FIGURE 46-10 A. Allergic contact dermatitis, acute phase, with sharply demar-cated, weeping, eczematous plaques in a perioral distribution. B. Allergic contactdermatitis to nickel, chronic phase demonstrating an erythematous, lichenified, weep-ing plaque on skin chronically exposed to a metal snap. (B, Courtesy of RobertSwerlick, MD.)

FIGURE 46-9 Erythema multiforme is characterized by multiple erythematous plaqueswith a target or iris morphology and usually represents a hypersensitivity reaction todrugs or infections (especially herpes simplex virus). (Courtesy of the Yale Resident’sSlide Collection.)

FIGURE 46-11 Urticaria showing characteristic discrete and confluent, edematous,erythematous papules and plaques.

is viewed under the microscope, the refractile hyphae will be seen

more easily when the light intensity is reduced and the condenser is

lowered. This technique can be utilized to identify hyphae in dermat-

ophyte infections (see Fig. 190-1), pseudohyphae and budding yeast

in Candida infections (see Fig. 187-1), and fragmented hyphae and

spores in tinea versicolor. The same sampling technique can be used

to obtain scale for culture of selected pathogenic organisms.

Tzanck Smear A Tzanck smear is a cytologic technique most often used

in the diagnosis of herpesvirus infections [simplex or varicella-zoster

(see Figs. 164-1 and 164-3). An early vesicle, not a pustule or crusted

lesion, is unroofed, and the base of the lesion is scraped gently with a

scalpel blade. The material is placed on a glass slide, air-dried, and

stained with Giemsa or Wright’s stain. Multinucleated epithelial giant

cells suggest the presence of herpes, but culture or immunofluores-

cence testing must be performed to identify the specific virus.

Diascopy Diascopy is designed to assess whether a skin lesion will

blanch with pressure as, for example, in determining whether a red

lesion is hemorrhagic or simply blood-filled. For instance, urticaria

(Fig. 46-11) will blanch with pressure, whereas a purpuric lesion

caused by necrotizing vasculitis (Fig. 46-4) will not. Diascopy is per-

formed by pressing a microscope slide or magnifying lens against a

lesion and noting the amount of blanching that occurs. Granulomas

often have an “apple jelly” appearance on diascopy.

Wood’s Light A Wood’s lamp generates 360-nm ultraviolet (or

“black”) light that can be used to aid the evaluation of certain skin

disorders. For example, a Wood’s lamp will cause erythrasma (a su-

perficial, intertriginous infection caused by Corynebacterium minutis-

simum) to show a characteristic coral red color, and wounds colonized

by Pseudomonas to appear pale blue. Tinea capitis caused by certain

dermatophytes such as Microsporum canis or M. audouini exhibits a

yellow fluorescence. Pigmented lesions of the epidermis such as freck-

les are accentuated, while dermal pigment such as postinflammatory

hyperpigmentation fades under a Wood’s light. Vitiligo (Fig. 46-12)

Part II Cardinal Manifestations and Presentation of Diseases288

FIGURE 46-12 Vitiligo in a typical acral distribution demonstrating striking cutaneousdepigmentation, as a result of loss of melanocytes.

appears totally white under a Wood’s lamp, and previously unsus-

pected areas of involvement often become apparent. A Wood’s lamp

may also aid in the demonstration of tinea versicolor and in recognition

of ash leaf spots in patients with tuberous sclerosis.

Patch Tests Patch testing is designed to document sensitivity to a spe-

cific antigen. In this procedure, a battery of suspected allergens is

applied to the patient’s back under occlusive dressings and allowed to

remain in contact with the skin for 48 h. The dressings are removed,

and the area is examined for evidence of delayed hypersensitivity re-

actions (e.g., erythema, edema, or papulovesicles). This test is best

performed by physicians with special expertise in patch testing and is

often helpful in the evaluation of patients with chronic dermatitis.

FURTHER READING

ARNDT KA et al (eds): Cutaneous Medicine and Surgery, An Integrated Pro-gram in Dermatology. Philadelphia, Saunders, 1996

CHAMPION RH et al (eds): Textbook of Dermatology, 6th ed. Oxford, Black-well Scientific, 1999

DERMATOLOGY LEXICON PROJECT: www.dermatology lexicon.orgFREEDBERG IM et al (eds): Fitzpatrick’s Dermatology in General Medicine,

5th ed. New York, McGraw-Hill, 1999

47ECZEMA, PSORIASIS, CUTANEOUS INFECTIONS, ACNE, AND OTHERCOMMON SKIN DISORDERSCalvin O. McCall, Thomas J. Lawley

TABLE 47-1 Clinical Features of Atopic Dermatitis

1. Pruritus and scratching2. Course marked by exacerbations and remissions3. Lesions typical of eczematous dermatitis4. Personal or family history of atopy (asthma, allergic rhinitis, food

allergies, or eczema)5. Clinical course lasting longer than 6 weeks FIGURE 47-1 Atopic dermatitis with hyperpigmentation, lichenification, and scaling

in the antecubital fossae. (Courtesy of Robert Swerlick, MD.)

ECZEMA AND DERMATITIS

Eczema, or dermatitis, is a reaction pattern that presents with variable

clinical and histologic findings and is the final common expression for

a number of disorders, including atopic dermatitis, allergic contact and

irritant contact dermatitis, dyshidrotic eczema, nummular eczema, li-

chen simplex chronicus, asteatotic eczema, and seborrheic dermatitis.

Primary lesions may include papules, erythematous macules, and ves-

icles, which can coalesce to form patches and plaques. In severe ec-

zema, secondary lesions from infection or excoriation, marked by

weeping and crusting, may predominate. Long-standing dermatitis is

often dry and is characterized by thickened, scaling skin (lichenifica-

tion).

ATOPIC DERMATITIS Atopic dermatitis (AD) is the cutaneous expression

of the atopic state, characterized by a family history of asthma, hay

fever, or dermatitis in up to 70% of patients. Some of the features of

atopic eczema are shown in Table 47-1. The prevalence of atopic der-

matitis is increasing worldwide, with a point prevalence in Norwegian

school children as high as 23%.

The etiology of AD is only partially defined, but there is a clear

genetic predisposition. When both parents are affected by AD, over

80% of their children manifest the disease. When only one parent is

affected, the prevalence drops to slightly over 50%. Patients with AD

may display a variety of immunoregulatory abnormalities including

increased IgE synthesis; increased serum IgE; increased specific IgE

to foods, aeroallergens, bacteria, and bacterial products; increased ex-

pression of CD23 (low-affinity IgE receptor) on monocytes and B

cells; and impaired delayed type hypersensitivity reactions.

The clinical presentation often varies with age. Half of patients with

AD present within the first year of life, and 80% present by 5 years of

age. About 80% ultimately coexpress allergic rhinitis or asthma. The

infantile pattern is characterized by weeping inflammatory patches and

crusted plaques that occur on the face, neck, and extensor surfaces. The

childhood and adolescent pattern is marked by dermatitis of flexural

skin, particularly in the antecubital and popliteal fossae (Fig. 47-1). AD

may resolve spontaneously, but over half of all individuals affected as

children will have dermatitis in adult life. The distribution of lesions

may be similar to those seen in childhood. However, adults frequently

have localized disease, manifesting as hand eczema or lichen simplex

chronicus (see below). In patients with localized disease, AD may be

suspected because of a typical personal history, family history, or the

presence of cutaneous stigmata of AD such as perioral pallor, an extra

fold of skin beneath the lower eyelid (Dennie’s line), increased palmar

skin markings, and an increased incidence of cutaneous infections, par-

ticularly with Staphylococcus aureus. Regardless of other manifesta-

tions, pruritus is a prominent characteristic of AD and is exacerbated by

dry skin. Many of the cutaneous findings in affected patients, such as

lichenification, are secondary to rubbing and scratching.