Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2853_Библиотеки_им_академика_М_И_Перельмана
.pdf
106 CHAPTER 6: The Skin and Nails
https://t.me/medicina_free
Hair. The skin is covered with hairs except on the palms, soles, dorsal distal phalanges, glans penis, inner surface of the prepuce, and labia minora.
Adults have two types of hair. Both sexes are covered in soft, colorless, short
vellus hairs. Terminal hairs are longer, coarser, and darker than vellus hairs.
Terminal hair is found on the scalp, pubic region, and axillae of both sexes.
Males often exhibit terminal hair on the trunk, face, and extremities. The hair
follicle is a tubular invagination of epidermis and dermis often extending into
the subcutaneous tissue. The proximal root terminates in a hollow bulb that
ts over a dermal structure, the papilla. Molecular signals between papilla
and follicle determine the stage of hair growth: active growth (anagen), regression (catagen), or rest (telogen). The long slender hair shaft is round or oval in
straight hairs and attened in a curled hair. The shaft has a medulla, which is
frequently absent, a cortex, containing pigment in colored hairs, and a supercial single layer of at scales, the cuticle. The root is softer and lighter in
color than the shaft. Hair follicles penetrate the dermis obliquely forming an
obtuse angle with the undersurface of the skin containing the involuntary
arrector pili muscles extending from near the hair bulb to the supercial dermis. Contraction pulls the hair perpendicular to the skin surface producing
“goosebumps” or “gooseesh.”
Sebaceous glands.
duce sebum through holocrine secretion into a duct emptying into the follicle
near its distal end; one or more sebaceous glands are associated with each
follicle. Sebaceous glands are most dense on the face and back.
Eccrine (Sweat) glands.
mis or subcutaneous tissue. A straight duct leads through the epidermis
emerging on the skin surface in a funnel-shaped pore. Only the vermilion
border of the lips, nail beds, labia minora, male prepuce, and glans penis lack
eccrine glands. They are necessary for cooling through evaporation of sweat.
They receive primarily cholinergic innervation from the autonomic nervous
system.
Apocrine glands.
active during puberty and are limited to the axillae, breasts, eyelids, genital,
and perianal skin. They have both cholinergic and adrenergic innervation.
The function of apocrine glands in humans is uncertain.
Nerves. The skin contains nerves transmitting a multiplicity of stimuli.
Meissner corpuscles in the dermal papillae convey light touch. Pacinian corpuscles in the deep dermis and subcutaneous tissue transmit pressure and vibra-
tion. Noxious sensations such as pain, itch, and temperature are transmitted
by unmyelinated bers. Skin may become insensate as the result of injury,
disease, or developmental anomaly. The density of nerves varies greatly by
location. The ngertips and lips are two of the most sensitive areas, and the
back one of the least sensitive.
Circulation of the skin and mucosa. Most skin and mucous membrane
disorders involve the vascular system to some extent. The skin has a rich
anastomotic network of vessels, so ischemia implies obstruction of the larger
proximal arterioles or arteries.
Specialized cells in the hair follicle’s dermal lining pro-
The gland’s body is a coiled tube deep in the der-
Apocrine glands associated with hair follicles become
Examining the Skin and Nails 107
https://t.me/medicina_free
Cutaneous wound healing and repair. Healing occurs in three phases: inam-
mation, proliferation, and maturation. In the inammatory phase, platelets
provide hemostasis and release proinammatory cytokines. Neutrophils are
the rst immune cells to inltrate the wound. Macrophages derived from circulating monocytes arrive later but contribute more to wound healing. Along
with neutrophils they debride the wound helping prevent infection. In addition, by releasing growth factors and cytokines, they affect tissue remodel-
The skin has a remarkable ability to repair injury. Injury into the dermis
ing.
heals with scarring, whereas epidermal wounds typically heal without scarring. Two weeks after injury and appropriate wound closure, skin strength is
~10% of normal. Collagen in the scar remodels for up to a year after injury
approaching 80% of normal strength. Multiple factors adversely affect wound
healing Chief among these is infection, which delays or halts healing. Wellvascularized tissue heals faster and better than less vascular tissues evident
by the rapid healing of richly vascularized scalp and facial injuries compared
to slower healing of less well-vascularized lower leg wounds. Some patients
are genetically prone to slow healing and/or poor scar formation. Both oral
and topical corticosteroids inhibit collagen synthesis dramatically impeding
wound healing. Finally, the wound care regimen affects the speed and quality
of healing.
EXAMINING THE SKIN AND NAILS
The skin is examined by inspection and palpation. Magnication with dermoscopy can provide details of individual lesions. Palpate for nodularity and
induration. Note the morphology and distribution of individual lesions and
the pattern of grouped lesions.
Evaluating Skin Turgor and Elasticity: Pinch and release a fold of skin (Fig. 6-3).
Normal skin rapidly attens into place. A persistent fold indicates loss of turgor (indicative of extracellular volume depletion) or elasticity (common in
sun exposed skin and the elderly).
Examining Nailfold Capillaries: Use an ophthalmoscope, dermatoscope,
or magnifying glass at 15–40x magnication. Select a nger without recent
trauma, placing a drop of immersion oil or lubricating jelly on the nail fold.
Normal capillary arcs are parallel narrow loops extending from the base of
the nail fold toward the nail and returning. Dilation, irregularity, and dropout
FIG. 6-3Testing for Skin Turgor.
108 CHAPTER 6: The Skin and Nails
https://t.me/medicina_free
of loops are abnormal. Abnormal capillaroscopy in a patient with Raynaud
phenomenon suggests dermatomyositis, systemic lupus erythematosus
(SLE), scleroderma, or another connective tissue disease.
SUPPLEMENTAL AIDS TO DERMATOLOGIC DIAGNOSIS
Magnification: Use a magnifying glass, otoscope, dermatoscope, or ophthal-
moscope to closely inspect lesions. Otoscopes and ophthalmoscopes provide
illumination and magnication.
Diascopy: Compress red lesions with a magnifying glass or a glass slide.
Blanching is indicative of dilated vessels; extravasated blood does not blanch.
See Fig. 6-4.
KOH Preparation: KOH preparations visualize dermatophyte hyphae,
Candida pseudohyphae, budding yeasts, and the spores and fragmented
hyphae of tinea versicolor. Scrape skin scales from the lesion onto a glass slide.
Adding two drops of a 10% to 20% KOH solution dissolves keratin allowing
fungal elements to be more easily seen. Gentle heating catalyzes this process
but avoid boiling the solution. Alternatively, KOH with Dimethyl Sulfoxide
(DMSO) can be used to help catalyze the process without having to be heated.
Start at scanning magnication then move to 10–20x higher power. Hyphae
appear as thin, elongated laments extending beyond cell walls, often best
seen slightly out of the plane in which the keratinocytes are in focus. Hyphae
may be difcult to distinguish from the outline of a keratinocyte. Other confounders include hair and clothing bers.
FIG. 6-4Petechia Confirmed by Diascopy. Several red vascular markings are seen on the index fingertip. Diascopy
discloses that the lesions do not blanch and are therefore extravasated blood.
Skin and Nail Symptoms 109
https://t.me/medicina_free
Tzanck Smear: To identify herpes simplex or varicella-zoster viruses in vesic-
ular lesions, rmly scrape the base of an unroofed early vesicle with a scalpel
and air dry the specimen on a glass slide. Stain it with Wright or Giemsa
stain and examine microscopically for characteristic cytopathic changes such
as multinucleated giant cells or ballooning keratinocytes. Perform PCR (polymerase chain reaction) or DFA (direct uorescent antibody) test on a fresh
specimen for virus identication.
Wood Light: Ultraviolet illumination (360 nm) uoresces scalp infections
caused by some dermatophytes, e.g., Microsporum canis (yellow), Pseudomonas
abscesses (pale blue), and intertriginous infections with Corynebacterium
minutissimum (coral red). Bathing removes some uorescent material leading to a falsely negative result. Wood light also can be helpful in evaluating depigmented skin conditions (vitiligo) and differentiating them from
hypopigmented lesions.
Skin Biopsy: Skin is biopsied using a skin punch, shaving with a scalpel or
razor blade, and by sharp excision.
SKIN AND NAIL SYMPTOMS
Itching (Pruritus): Itching is a common symptom and optimal treatment requires
a specic diagnosis. Describe the onset, location, severity, and course whether
constant or progressive. Determine aggravating and ameliorating factors. Ask
about new medications. Excoriations and lichenication indicate scratching.
CLINICAL OCCURRENCE: Local Causes: Contact dermatitis (e.g., poison
ivy), insect bites, chigger bites (red larva of Trombiculidae mites), scabies,
tinea, candidiasis, trichomoniasis, atopic dermatitis, neurodermatitis, seborrheic dermatitis, lichen simplex, urticaria, pruritus ani, pruritus vulvae,
stasis dermatitis, dermatitis herpetiformis, miliaria (heat rash), nostalgia
paresthetica;
nancy, pityriasis rosea, psoriasis, medication reactions, uremia, obstructive
jaundice, biliary cirrhosis, myxedema, polycythemia vera (aquagenic pruritus), Hodgkin disease, cutaneous and other lymphomas, diffuse cutaneous
mastocytosis, pediculosis (body lice), hook worm, onchocerciasis, lariasis.
Systemic Causes: Asteatosis (“winter itch”), pruritus of preg-
SKIN AND NAIL SIGNS
Learning to accurately and completely describe observations using precise
terminology facilitates use of reference materials and provides accurate information for dermatologic referral or pathology requisition. Each sign is followed by examples of conditions associated with the lesion.
Distribution of Lesions: Many skin diseases have characteristic distribu-
tions, some determined by regional skin features and others by exposure to
noxious agents. The explanation for many distributions is unknown. Some
examples follow (Fig. 6-5).
Head and neck. Acne: Face, neck, and shoulders; Actinic Keratoses:
Face, scalp; Amyloidosis: Eyelids; Atopic Dermatitis: Face, neck; Cancer:
Face, nose, ears, lips; Contact Dermatitis: Eyelids, face; Discoid Lupus
110 CHAPTER 6: The Skin and Nails
Actinic keratosis
Lichen simplex chronicus
Tinea pedisPlantar warts
Condyloma acuminatum
https://t.me/medicina_free
FIG. 6-5Distribution of Skin Lesions.
Psoriasis
Acne vulgaris
Herpes zoster
Psoriasis
Hemorrhoids
Candida
Psoriasis
Basal cell
carcinoma
Seborrheic
keratosis
Seborrheic dermatitis
Rosacea
Acne vulgaris
Candida
Senile angioma
Atopic dermatitis
Common warts
Candida
Erythrasma
Psoriasis
Erythema nodosum
Stasis dermatitis
Skin and Nail Symptoms 111
https://t.me/medicina_free
Erythematosus: Nose, cheeks; Herpes Zoster: Trigeminal nerve distribution;
Psoriasis: Scalp; Rosacea: Mid-face; Seborrhea: Scalp, eyebrows, eyelids,
nasal alae;
Capitis:
Trunk.
Secondary Syphilis: Face; Spider Angiomas: Cheeks, neck; Tinea
Scalp; Xanthelasma: Eyelids; Varicella (chickenpox): Face.
Candidiasis: Under breasts, axillae, inguinal and gluteal folds;
Dermatitis Herpetiformis: Scapulae, sacrum, buttocks; Drug Eruption: Front
and back of thorax and abdomen;
Petechiae: Abdomen; Pityriasis Rosea: Front
and back of trunk; Secondary Syphilis: Thorax and abdomen; Spider Angiomas:
Chest, shoulders, abdomen; Varicella (chickenpox): Trunk and face.
Extremities.
Actinic Keratoses and Cancer: Backs of the hands; Atopic
Dermatitis: Antecubital fossae; Contact Dermatitis: Arms, hands, legs;
Erythema Multiforme: Arms, hands, legs, feet, palms, soles; Erythema
Nodosum: Legs, shins; Granuloma Annulare: Backs of hands and ngers;
Onychomycosis: Fingernails, toenails; Petechiae: Forearms, hands, legs, feet;
Pityriasis Rosea: Upper arms, upper legs; Plantar Warts: Soles; Psoriasis:
Elbows, knees, hands, ngernails; Secondary Syphilis: Palms, soles.
Pattern of Lesions: Single lesions may have distinctive shapes and patterns.
Sometimes individual lesions appear in distinctive congurations (e.g., herpes
zoster). Multiple individual lesions often coalesce into larger less-distinctive
patterns, so the evolution of lesions is critical.
Annular, arciform, and polycyclic pattern. The individual lesions are
arranged in circles, arcs, or irregular combinations of the two.
Examples:
Drug eruptions, erythema multiforme, urticaria, psoriasis, granuloma annulare, tinea, subacute cutaneous lupus.
Serpiginous pattern.
margins.
Examples: Larva migrans.
Target (Iris) pattern.
one ring may be present.
Irregular pattern.
Examples:
Urticaria and insect bites.
Dermatomal pattern.
do not cross the midline.
The lesions occur in wavy lines or have wavy, indented
A bull’s-eye pattern with an encircled round spot; more than
Examples: Erythema multiforme, erythema migrans.
Groups of individual lesions have no distinct pattern.
Lesions follow the spinal root sensory dermatome so
Examples: Herpes zoster.
Linear pattern.
Lesions follow linear cutaneous and subcutaneous structures
(e.g., nerves, lymphatics, or blood vessels), or contact with a linear irritant.
Examples:
Lymphangitis, supercial phlebitis, contact dermatitis (e.g., poi-
son ivy), jellysh envenomation, trauma, or other infections (sporotrichosis).
Lines of Blaschko. Many skin eruptions, including psoriasis and pityriasis
rosea, follow lines of fetal epidermal migration and proliferation.
Retiform pattern. Lesions reect the deep dermal and medium vessel arterial or venous anatomy. The venous pattern is a lacey network; arteriolar
112 CHAPTER 6: The Skin and Nails
A. Macule B. Papule
https://t.me/medicina_free
occlusion results in infarcts with angulated or nger-like borders. Examples:
Venous Pattern: Livedo reticularis; Arterial Pattern: Necrotizing vasculitis,
calciphylaxis, cutaneous emboli, arteriolar thrombosis.
Extrinsic pattern.
The lesions follow no anatomic pattern often having rela-
tively straight borders and/or shapes suggesting the pattern is impressed on
patient from outside.
Examples: Radiation injury, including sunburn and
radiation dermatitis, contact dermatitis.
Morphology of Individual Lesions: After noting distribution and pattern,
examine and characterize several individual lesions. Identify new, mature,
and resolving lesions. Palpate to identify papules, nodules, plaques, and inltration. Use diascopy to disclose lesions obscured by erythema and to distinguish vasodilation from extravasated blood.
Macules and patches. These are nonpalpable changes in skin color or
appearance (Fig. 6-6A). Macules are <1 cm and patches are ≥1 cm. The
borders can be sharp or indistinct. There may be desquamation or scaling.
Examples:
Freckles, exanthems (rubeola, rubella, secondary syphilis, rose
spots of typhoid fever), drug eruptions, petechiae, rst-degree burns, SLE,
pityriasis rosea, café-au-lait spots, vitiligo.
Papules.
and tops may be distinctive.
Papules are <1 cm lesions that are raised (Fig. 6-6B). The borders
Examples: Acuminate or Pointed: Bites, acne,
physiologic gooseesh; Flat-topped: Lichen planus, molluscum contagiosum,
condyloma latum; Round or Irregular: Angiomas, melanoma, eczematous
dermatitis, papular secondary syphilis; Filiform: Condyloma acuminatum;
Pedunculated: Skin tags, neurobromas.
Plaques.
A diffusely elevated area ≥1 cm in diameter is a plaque, often
formed from conuent papules. Plaques are characteristically at topped and
broader than high, like a plateau.
Examples: Cutaneous lymphomas (myco-
sis fungoides); Red, Scaling: Psoriasis, discoid lupus erythematosus (with
FIG. 6-6 Macules and Papules. A. Macules are visible but not palpable. B. Papules are palpable and <5 mm in
diameter.
A. Nodule B.Wheal
Skin and Nail Symptoms 113
https://t.me/medicina_free
atrophy); Yellow: Xanthomas; Brown: Seborrheic keratoses; Hyperkeratotic:
Plantar warts;
Nodules.
Lichenied: Atopic dermatitis.
Nodules are usually >1 cm in diameter, distinguished from pap-
ules by extension into the dermis or subcutaneous tissue (Fig. 6-7A). The skin
slides over nodules below the dermis; lesions within the dermis move with
the skin.
Examples: Rheumatoid nodules, lipomas, cysts, cancer, gouty tophi,
erythema nodosum, panniculitis.
Wheals.
Cutaneous edema produces circumscribed, irregular, and relatively
transient plaques (Fig. 6-7B), varying from red to pale depending on the
amount of uid in the skin. Hives (urticaria) often itch.
Examples: Urticaria,
insect bites.
Vesicles.
Fluid dissects the epidermis producing an elevation covered by
translucent epithelium that is easily punctured releasing the uid (Fig. 6-8A).
Vesicles are <1 cm in diameter.
Examples: Acute contact dermatitis, second-
degree burns, varicella, herpes simplex and zoster, smallpox.
Bullae.
Bullae are uid accumulations >1 cm in diameter dissecting within
or under the epidermis (Fig. 6-8A). Tense bullae indicate dissection below the
basal layer. Dissection supercial to the basal layer results in accid, more
easily ruptured bullae, often presenting as supercial erosions without intact
bullae.
Examples: Contact dermatitis, pemphigus, pemphigoid, erythema
multiforme (rarely), diabetic bullae, edema bullae.
Pustules.
Pustules are pus-lled vesicles or bullae (Fig. 6-8A). The contents
are milky, orange, yellow, or green. Pustules frequently arise from hair follicles or sweat glands.
Examples: Folliculitis, acne, furuncles, pustular pso-
riasis, bromide and iodide eruptions.
Cysts.
Cysts are papules or nodules containing uid or viscous material
enclosed by an epithelium (Fig. 6-8B). Pseudocysts are similar lesions without
FIG. 6-7Nodules and Wheals. A. Nodules are discrete and firm lesions in the skin or subcutaneous tissue often
without any epidermal changes. B. Wheals (hives) are transient, discrete areas of edema in the epidermis and dermis.
114 CHAPTER 6: The Skin and Nails
A. Vegetation B. Scales
A. Vesicle, bulla, or pustule B. Cyst
https://t.me/medicina_free
FIG. 6-8 Fluctuant Skin Lesions. A. Vesicle, bullae, and pustules involve the epidermis. B. Cysts are
subepidermal and may extend into the subcutaneous tissues.
an epithelial lining, a histological distinction. Examples: Epidermal inclusion
and pilar (trichilemmal) cysts; Pseudocysts: Cystic acne.
Vegetations.
Elevated irregular growths are called vegetations (Fig. 6-9A).
Verrucous lesions have keratotic or dried surfaces. Papillomatous lesions are
covered by normal epidermis.
Examples: Verrucous: Verruca vulgaris (com-
mon wart), seborrheic keratosis; Papilloma: Condyloma acuminatum.
Scales are thin plates of partly separated dried cornied epithelium
Scales.
adherent to the epidermis (Fig. 6-9B).
Examples: Large Scales: Psoriasis, exfo-
liative dermatitis; Small Scales: Pityriasis rosea, seborrheic dermatitis.
Hyperkeratosis.
ing thick elevated skin.
Keratotic cells do not slough normally, but pile up produc-
Examples: Calluses, seborrheic, and actinic keratoses.
Arsenic produces punctate keratoses of the palms and soles.
FIG. 6-9Vegetations and Scales. A. Vegetations are irregular growths above the skin surface. B. Scales are small
or large flakes of cornified epithelium loosely adherent to the skin surface.
A. Lichenification B. Crust
A. AtrophyB. Erosion
Skin and Nail Symptoms 115
https://t.me/medicina_free
FIG. 6-10Lichenification and Crusts. A. Lichenification is a leathery thickening of all skin layers with prominent
furrows. B. Crusts form from dried blood, serum, pus or other secretions from the skin.
Lichenication. Repeated rubbing promotes hyperplasia of all layers
(Fig. 6-10A) appearing as a dry plaque with accentuated skin lines.
Examples:
Atopic dermatitis, lichen simplex chronicus.
A supercial plate of dried serum, blood, pus, or sebum accumulates
Crusts.
on a ruptured vesicle or pustule (Fig. 6-10B) or on chronically inamed skin.
Examples:
Impetigo.
Atrophy.
The skin is thinned lacking normal skin lines (Fig. 6-11A).
Actinic atrophy, striae, discoid lupus erythematosus, effect from potent topical steroids, steroid injections, and insulin lipodystrophy.
Sclerosis. Collagen are deposited in cutaneous and subcutaneous tissues,
often a consequence of chronic inammation.
scleroderma (systemic and localized) and variants, morphea, nephrogenic
brosing dermopathy.
FIG. 6-11Atrophy and Erosion. A. Atrophy is thinning of all skin layers. B. Erosions represent traumatic loss of
the stratum corneum.
Examples:
Examples: Stasis dermatitis,
Соседние файлы в папке Библиотека им академика М.И. Перельмана