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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.