A resident physician’s perspective

Review the basic anatomy of the integumentary system

Review how to approach the dermatologic examination

Recognize basic skin lesions and patterns Review of some dermatologic

manifestations of systemic disease

A.Epidermis (external skin surface) ◦ 1.Keratinised squamous epithelium◦ 2.Thickness

a.Eyelids: 0.05 mm b.Palms and soles: 1.5 mm

B.Dermis (supports epidermis) ◦ 1.Thick, dense, fibroelastic connective tissue◦ 2.Highly vascularized◦ 3.Contains sensory receptors

C.Hypodermis (Subcutaneous layer) ◦ 1.Loose connective tissue with adipose tissue

A.Stratum Corneum (Cornified Layer) ◦ 1.Outermost layer of epidermis◦ 2.Composed mostly of keratin (fibrous protein)◦ 3.Cells desquamated (27 days after production)

B.Stratum Lucidum (present only in very thick skin) C.Stratum Granulosum (Granular Layer)

◦ 1.Darker layer with intracellular granules◦ 2.Produces keratin

D.Stratum Spinosum (Prickle Cell Layer) ◦ 1.Composed of keratinocytes◦ 2.Cells produced by basal layer and growing◦ 3.Keratin production starts

E.Stratum Germinativum (Stratum Basale, Basal Cell Layer) ◦ 1.Innermost layer of epidermis◦ 2.Cells are produced here in the germinal layer◦ 3.Forms the prickle cells in the layer above

A.Hair Follicle◦ 1.Hair producing unit based in Hypodermis◦ 2.Cylinder that ascends through surface epithelium◦ 3.Hair held within center of follicle's cylinder◦ 4.Entire follicle encased in connective tissue

B.Sweat Gland◦ 1. Merocrine and apocrine

C.Sebaceous Gland◦ 1. Secrete sebum

D.Melanocyte◦ 1. Melanin (brown pigment) produced within melanosome

E.Merkel's Cell F.Langerhans Cells (in Prickle Layer)

◦ 1.Dendritic histiocytic cells◦ 2.Intercept antigenic signal and pass to lymphoid cells

G.Desmosome (Macula adherens) ◦ 1.Intercellular bridge that attaches epidermal cells◦ 2.Small dense Plaque with protruding tonofilaments

A.Sensation (largest sensory organ in the body) B.Protection

◦ 1.Prevents dehydration◦ 2.Prevents infection◦ 3.Physical barrier to injury◦ 4.Protects against ultraviolet light injury (Melanin)

C.Thermoregulation ◦ 1.Insulation (hair and adipose tissue)◦ 2.Heat dissipation

a.Sweat evaporation b.Increased blood flow

D.Metabolic ◦ 1.Energy storage of Triglycerides in adipose tissue◦ 2.Vitamin D synthesis

Use magnification◦ Feel lightly◦ Palpate deeply

Distribution◦ Local patterns - groups, rings, lines

Look at nails, hair, mucus membranes, hands, feet◦ nail pitting for psoriasis◦ scalp may be clue to seborrhea elsewhere◦ lichen planus with a white lacy pattern in the mouth◦ fungal infection on the feet and hand

Think pathophysiology Infections Inflammatory Processes - dermatitis,

seborrhea Acne and related disorders Immunologic Benign and premalignant growths Malignancies

An extensive language has been developed to standardize the description of skin lesions, including◦ Primary morphology (lesion type)◦ Secondary morphology (configuration)◦ Texture◦ Distribution◦ Color

Macule◦ A macule is a change in the

color of the skin. It is flat; if you were to close your eyes and run your fingers over the surface of a purely macular lesion, you could not detect it. A macule greater than 1 cm. may be referred to as a patch.

Papule◦ A papule is a solid raised

lesion that has distinct borders and is less than 1 cm in diameter. Papules may have a variety of shapes in profile (domed, flat-topped, umbilicated) and may be associated with secondary features such as crusts or scales.

Nodule◦ A nodule is a raised solid

lesion more than 1 cm. and may be in the epidermis, dermis, or subcutaneous tissue.

Plaque◦ A plaque is a solid, raised,

flat-topped lesion greater than 1 cm. in diameter. It is analogous to the geological formation, the plateau.

Vesicles◦ Vesicles are raised lesions less than 1 cm. in

diameter that are filled with clear fluid.

Wheal◦ A wheal is an

area of edema in the upper epidermis.

Telangiectasia◦ Telangiectasia are

the permanent dilatation of superficial blood vessels in the skin and may occur as isolated phenomena or as part of a generalized disorder, such as ataxia telangiectasia.

Configuration is the shape of single lesions and the arrangement of clusters of lesions.◦ Linear lesions take on the shape of a straight line

and are suggestive of some forms of contact dermatitis, linear epidermal nevi, and lichen striatus.

◦ Annular lesions are rings with central clearing. Examples include granuloma annulare, some drug eruptions, some dermatophyte infections (eg, ringworm), and secondary syphilis.

◦ Nummular lesions are circular or coin-shaped; an example is nummular eczema.

◦ Target (bull's-eye or iris) lesions appear as rings with central duskiness and are classic for erythema multiforme.

◦ Serpiginous lesions have linear, branched, and curving elements. Examples include some fungal and parasitic infections (eg, cutaneous larva migrans).

◦ Reticulated lesions have a lacy or networked pattern. Examples include cutis marmorata and livedo reticularis.

◦ Herpetiform describes grouped papules or vesicles arranged like those of a herpes simplex infection.

◦ Zosteriform describes lesions clustered in a dermatomal distribution similar to herpes zoster.

Many systemic diseases have skin changes associated with them

In some cases, the cutaneous manifestations may be the first or most obvious sign

Sarcoidosis◦ The skin is involved in 15% to 35% of cases◦ Lesions may present as:

Lupus pernio (red swelling of the nose) Translucent papules around the eyes and nose Annular lesions with central atrophy Nodules on the trunk and extremities Scar sarcoid

◦ Erythema nodosummay be associated with acute sarcoidosis

Granulomatosis◦ Skin lesions in up to 60% of cases◦ Lesions include purpura, nodules and infarcts

Pseudoxanthoma elasticum◦ Papaules in distribution◦ Degeneration of elastic fibres◦ Associated with stroke, myocardial infarction,

peripheral vascular disease, GI hemorrhage Ehlers-Danlos syndrome

◦ Skin hyperextensibility◦ Associated with angina, peripheral vascular

disease, GI hemorrhage Erythema marginatum

◦ Associated with acute rheumatic fever

Osler-Weber-Rendu syndrome◦ Nosebleeds and gastrointestinal bleeds◦ Cutaneous and mucosal telangiectasias

Dermatitis herpetiformis◦ Immune-mediated bullous disease◦ Associated with gluten-sensitive enteropathy

Uremic pruritus◦ Associated with end-stage renal disease

Ataxia-telangiectasia◦ Cutaneous and ocular telangiectasia, cerebellar

ataxia, choreoathetosis, recurrent lung infections Tuberous sclerosis

◦ Hyperpigmented macules, fibromas, epilepsy Sturge-Weber-Dimitri syndrome

◦ Capillary angioma in distribution of the upper or middle branch of the trigeminal nerve

Psoriatric arthritis◦ Occurs in 5% to 8% of patients with psoriasis

Reiter syndrome◦ Triad of urethritis, conjunctivitis, and arthritis

Erythema migrans◦ Annular plaque presentation of Lyme disease, a

spirochete infection following an infected tick bite Lupus erythematosus

◦ Cutaneous abnormalities occur in 80% of patients

Diabetes◦ Necrobiosis lipoidica diabeticorum

Yellow brown atrophic telangiectatic plaques on shins

Granuloma annulare◦ Papular eruption possibly associated with

diabetes Pretibial myxedema

◦ Associated with Graves disease

Clubbing Inflammatory bowel disease, pulmonary malignancy, asbestosis, chronic bronchitis, COPD, cirrhosis, congenital heart disease, endocarditis, atrioventricular malformations, fistulas KoilonychiaIron deficiency anemia, hemochromatosis, Raynaud’s disease, SLE, trauma, nail-patella syndrome OnycholysisPsoriasis, infection, hyperthyroidism, sarcoidosis, trauma, amyloidosis, connective tissue disorders

PittingPsoriasis, Reiter’s syndrome, incontinentia pigmenti, alopecia areata Beau’s linesAny severe systemic illness that disrupts nail growth, Raynaud’s disease, pemphigus, trauma Yellow nailLymphedema, pleural effusion, immunodeficiency, bronchiectasis, sinusitis, rheumatoid arthritis, nephrotic syndrome, thyroiditis, tuberculosis, Raynaud’s disease

Terry’s (white) nails Hepatic failure, cirrhosis, diabetes mellitus, CHF, hyperthyroidism, malnutrition Azure lunula Hepatolenticular degeneration (Wilson’s disease), silver poisoning, quinacrine therapy Half-and-half nails Specific for renal failure Muehrcke’s lines Specific for hypoalbuminemia Mees’ lines Arsenic poisoning, Hodgkin’s disease, CHF, leprosy, malaria, chemotherapy, carbon monoxide poisoning, other systemic insults

Dark longitudinal streaks Melanoma, benign nevus, chemical staining, normal variant in darkly pigmented people Longitudinal striations Alopecia areata, vitiligo, atopic dermatitis, psoriasis Splinter hemorrhage Subacute bacterial endocarditis, SLE, rheumatoid arthritis, antiphospholipid syndrome, peptic ulcer disease, malignancies, oral contraceptive use, pregnancy, psoriasis, trauma Telangiectasia Rheumatoid arthritis, SLE, dermatomyositis, scleroderma