Skin, Hair, Nails

You might also find a fair amount of useful information at the following links and "pages."
Review of Anatomy and Histology of the Skin. Normal skin,
Dermatology Assessment - Terms and Issues
Lesion Examination

  • Skin, hair, nail disorders
    • Very common complaints
    • Difficult to describe & diagnosis
      • Talk about assessment of skin disease, characteristics, terminology
      • Illustrate some of the more common disorders.
    • Body function efficiency
      • Function within narrow temperature, hydration limits
      • Skin encapsulates, insulates, thermoregulates.
      • Link in immune system
      • Dermis - Langerhans cells important delayed hypersensitivity reactions, allograft rejection
      • Endocrine function - modification of gonadal & adrenal sex hormones
      • Site of vitamin D synthesis.
  • Two skin layers
    • Epidermis (from ectoderm)
    • Dermis and hypodermis (from mesoderm).
  • Epidermis
    • Modified stratified squamous epithelium
      • Migrate to surface through cell layers, lose nuclei, form tough superficial barrier.
      • Migratory cycle approx 30d Cornified cells shed about 14 days later.
      • Transit time abnormality Ð ex. psoriasis (accelerated migration)
  • Epidermal cells
    • Linked by structures: desmosomes
    • Rest on thin basement membrane anchored to dermis by proteins
    • Important in dz pathogenesis at epidermal-dermal junction (e.g. bullous pemphigoid)
  • Melanocytes
    • Develop among basal cells
    • Skin & hair pigmentation.
      • Protects from ultraviolet irradiation.
  • Albinism
    • Skin color determined by #, size, distribution of melanin granules, not # melanocyte cells.
      • Hereditary failure to synthesize melanin _ albinism.
      • Skin, hair - white.
      • Eyes pink - absent iris pigmentation (may show nystagmus).
  • Dermis
    • Supporting framework for epidermis
    • Fibrous matrix collagen & elastin
    • Skin appendages with nerves, blood vessels, fibroblasts, various inflammatory cells.
  • Dermis
    • Divided into two layers:
      • Synthesize, secrete dermal collagen & elastin.
      • Disruption of dermal elastin, _ wrinkles, loose skin syndrome.
  • Hypodermis
    • Dermis rests on hypodermis (subcu layer of fat, loose connective tissue).
    • Serves both as fat store and insulating layer.
  • Appendages
    • Formed from epidermis invaginating into dermis
      • Eccrine (sweat) glands
      • Apocrine glands
      • Sebaceous glands
      • Hair
      • Nails
  • Sebaceous Glands
    • Can function throughout life
    • Activity latent between birth and puberty
    • Partly responsible for vernix caseosa production - covers, waterproofs fetus during latter stages of gestation.
    • Become particularly active during puberty. Secretion is holocrine: stimulated by androgens, opposed by estrogens.
    • Glands absent from palms & soles
    • Concentrated - face, scalp, midline of back, perineum.
  • Sebum
    • Contains triglyceride, scalene and wax esters
    • Functions to waterproof & lubricate the skin
    • Inhibits growth of skin flora & fungi
    • Skin disorders (acne vulgaris, rosacea) occur where sebaceous glands concentrate
  • Apocrine Glands
    • Concentrated in axillae, areolae, nipples, anogenital regions, eyelids, external ears.
    • Become functionally active at puberty - responsible for odorless secretion acted on by skin flora causing characteristic body odor to develop.
  • Eccrine Glands
    • Sweat glands - widely distributed, important in heat regulation/fluid balance.
    • Secretion/modification - cholinergic & hormonal control.
    • Sweating - response to temp change.
    • Under hypothalamic control.
  • Hair
    • Mammals - important in temperature control.
    • Man - mainly tactile organ, sensual function: sexual attraction, stimulation.
    • Covers all except palms, soles, prepuce, glands, inner labia minora.
    • Inspect/palpate - distribution, texture, amount
  • Hair
    • Gestation: fetus lanugo - lost shortly before birth
    • May be vellus (short, fine, unpigmented) or terminal (thicker, pigmented).
    • Puberty - development of coarse, pigmented hair in pubic, axillary, facial distribution.
  • Alopecia
    • Balding (alopecia) worries pts
    • Male pattern baldness common
      • Slow onset hair loss, receding hairline from frontal, temporal scalp & crown.
      • Family hx baldness (male alopecia) autosomal dominance, may begin early in life.
      • Post menopause, many note thinning of the hair. Often with facial hair growth
  • Hair loss
    • Feature of dz? Alopecia characteristics may be helpful.
    • C/O localized alopecia (alopecia areata)? Autoimmune disease (e.g. Hashimoto's thyroiditis)
  • Hair loss
    • Stress or anxiety neurosis? May pluck hair _ local area thinning, baldness.
    • Severe illness, malnutrition, sudden psychological shock ->loss usually recovers with stress resolution.
  • Patient considerations
    • Warn pts undergoing cytotoxic cancer tx - expect generalized hair loss.
    • Failure to develop axillary & pubic hair - possible pituitary or gonadal dysfunction.
  • Abnormal hair growth
    • Distressing symptom in women.
    • Some facial hair growth - natural in postpubertal women.
    • Racial differences: least apparent Japanese, Chinese women; most apparent Mediterranean, Middle Eastern, Indian, African extraction.
    • Hx - previous problems, pattern changes, systemic problems.
  • Abnormal facial hair growth
    • Hirsute - S&S virilism, possible hormonal imbalance.
  • Nails
    • Specialized skin appendage
    • Derived from epidermal tuck - invaginates into dermis. Highly keratinised epithelium, strong but flexible
    • Provides sharpened surface for fine manipulation, clawing, scraping or scratching.
  • Nail - 3 major components
    • Root, nail plate, free edge
      • Proximal, lateral nail folds overlap nail edges
      • Thin cuticular fold (eponychium) overlies proximal nail plate
      • Lunula crescent-shaped portion of proximal nail
      • Free margin - distal nail continuous with hyponychium, (specialized area thickened epidermis).
  • Nail plate
    • On highly vascularized nail bed - gives pink appearance.
    • Paronychium - soft, loose tissue around nail border
      • Susceptible to infiltrating infection from breach in eponychium (a paronychia).
    • Fingernails grow approximately 0.1 mm/d, increased in summer.
  • Nails
    • Inspect/palpate - pitting, thickening, color change
    • May be revealing, but nail-related symptoms usually nonspecific.
    • S&S suggest nail edge bacterial infection: intense pain, swelling, often purulent discharge.
    • C/O brittleness, splitting,cracking _ little diagnostic information.
    • Ask Hx skin or systemic dz, that may affect nails:
      • Psoriasis, severe eczema
      • Lichen planus
      • Susceptible to bacterial, fungal skin infection.
  • Skin History
    • Skin readily examined so hx may seem less important than with other systems.
    • Thorough hx may unearth crucial information to aid dx.
    • Evaluate possible precipitating factors.
  • Patient's social conditions
    • Overcrowding, close physical contact - important considerations with infectious disorders (e.g. scabies, impetigo)
    • Possible precipitating factors? Contact with occupational or domestic toxins or chemicals.
  • Questions
    • Waterproof gloves worn with housework?
    • Recent exposure to medicines?
    • Cosmetics - impt cause skin sensitization: new soaps, deodorants, toiletries?
    • Systemic disorders may present skin symptoms.
  • Ask about hobbies
    • Gardening, model building, photo developing?
    • Foreign travel, insect bites?
    • Is the skin complaint seasonal?
    • Infectious dzs often present skin rashes, lesions.
      • Recent sore throat? Streptococcal infection with rash (scarlet fever)
  • Questions?
  • More Hx Examples
    • Cutaneous candidal infection - itchy rash & sore tongue. Women - vaginal discharge.
    • Yeast (Candida albicans) infection - broad-spectrum antibiotics.
    • Photosensitive rashes: sun-exposed areas (without strong sunburn) - systemic lupus erythematosis, porphyria, Rx.
  • Pruritus
    • C/O genital skin lesions - possible STD contact.
    • AIDS? - nodular lesions characteristic of Kaposi's sarcoma or thrush affecting mucosa or skin.
    • Hx risk factors important (e.g. male homosexuality, high-risk heterosexual contact, blood transfusion, IV drug abuse).
    • Skin itching (pruritus) - absence of obvious rash consider underlying systemic disorder 
  • Treatment Questions
    • Always ask about topical tx - may alter skin lesion appearance, makes assessment, dx more difficult.
    • Topical steroids, other topical substances OTC or prescribed?
  • Inspection/Palpation
    • Skin exam -- tendency to focus on local area noticed by pt.
    • Consider skin an organ. Examine whole organ to gain max information.
    • Strip pt to underwear, cover with gown, blanket
    • Well lighted area.
    • Assess if skin problem localized or manifestation of systemic illness.
  • Skin Exam
    • Scan skin, look for lesions, note position and symmetry.
    • Expose hidden areas - axillae, inner thighs, buttock.
    • Many lesions Dx by appearance, localization.
    • Unlike other exams - relies almost entirely on careful inspection, meticulous descriptive terminology.
  • Lesion Assessment
    • Measure lesion length, breadth monitoring progression or regression.
    • Light helps define skin lesions
      • Borders - transilluminaton.
      • Fluid-filled, not solid lesion - red glow light shining through.
      • Wood's lamp - distinguish fluorescing lesion; blue-green fluorescence of fungal infections.
  • Skin Color
    • Varies between individuals, races
    • Usually even, symmetrical distribution.
    • Normal variations with freckling, sun-exposure.
    • Pregnancy - darken skin over cheekbones (melasma), areola around nipple (chloasma).
  • Abnormal Skin Color
    • Generalized changes occur in jaundice, iron overload, endocrine disorders, albinism.
    • Yellow tinge of jaundice best observed in good daylight, initial yellow sclera _ trunk, arms, legs.
    • Long-standing, deep obstructive jaundice, may be deep yellow-green.
    • Eating large quantities carrots, or other vitamin A may develop carotenemia without scleral discoloration -distinguishes it clinically from jaundice.
  • Skin colors & dz
    • Iron overload (hemosiderosis, hemochromatosis) causes skin to turn slate-gray color.
    • Addison's disease (adrenal destruction) _ skin darkening 1st palmar creases _ soles, scars, other skin creases. Mouth, gums mucosa also becomes pigmented.
    • Hypopituitarismskin is soft, pale and wrinkled.
  • Erythema (redness)
    • Caused by capillary dilatation
    • With pressure red lesion blanches, reforms.
    • Ex. erythematous flush in necklace area. Cause = anxiety?
  • Redness variations
    • Petechiae - small < 5 mm
    • Purpura - larger > 5mm
    • Ecchymoses (bruise) - non blanchable, variable size.
  • Bruising
    • Traumatic bruises - ecchymoses.
    • Telangiectasia - fine blanching vascular lesions from superficial capillary dilatation.
  • Skin Assessment
    • Most skin disorders Dx by appearance & Hx, therefore assessment very important.
    • Special techniques: skin biopsies, scrapings, immunofluorescent staining, culture may be required to confirm Dx.
  • Skin Lesions
    • Flat, circumscribed color changes
      • Macule if < 1cm (freckle) without elevation or depression.
    • Flat, circumscribed color change
      • Patch if > 1 cm.
    • Raised, palpable? Assess if papule.
      • Solid elevated, circumscribed, < 1cm.
    • Raised, palpable? Assess if plaque.
      • Elevated, firm, rough, flat top, > 1cm.
    • Raised, palpable? Assess if nodule.
      • Solid lesion >1cm< 2cm. In epidermis, dermis or subcu
    • Raised, palpable? Assess if wheal.
    • Raised, palpable? Assess if tumor. Solid, demarcated? Dermis, >2cm
  • Describing Lesions
    • Circumscribed, elevated, fluctuant, serous fld-filled? Assess if vesicle.
    • Circumscribed, elevated, fluctuant, fluid-filled? Assess if bulla.
    • Circumscribed, elevated, fluctuant, purulent fld-filled? Assess if pustule.
  • Inspecting Skin Lesions
    • General considerations
    • Color - melanin, hormones, UV, carotenoids, oxyHgb, < Hgb
    • Moisture - wetness or dryness of skin
    • Turgor - tissue hydration
    • Mucous membranes - oral, ocular, genital
  • Configuration
    • Linear - factitial, nevoid, autoinoculation.
    • Annular - ring-like-tinea
  • Distribution
    • Light exposed - LE, Rx, seborrheic dermatitis, acne vulgaris , acute contact dermatitis
    • Generalized - drug, infection
    • Palms/soles - syphilis , RMSpot Fever, erythema multiforme
  • Distribution
    • Intertriginous - Candida, tinea.
    • Flexor/extensor
  • Inspecting Skin Lesions
    • Careful descriptions of size, shape, color, texture, position - helpful in dx.
    • Ascertain primary & 2ndary description of lesion.
    • Primary - decide if lesion flat, nodular, fluid-filled?
  • Describing Lesions
    • If possible, describe the arrangement of the lesions -- whether linear, annular (ring-shaped) or clustered.
      • Shingles (herpes zoster) - rash occurs in distribution of one or more skin dermatomes..
    • Add 2ndary characteristics to description
      • Superficial erosions, ulceration, crusting,atrophy, excoriation, scaling, fissuring, lichenification, atrophy, excoriation, scarring, keloid formation, necrosis.
        • Used to decide if lesion is flat, raised, tender.
        • Compression may be helpful.
        • Telangiectasia - dilated superficial blood vessels.
  • Palpation
    • Use back of hand to assess temperature.
      • Inflamed lesions (e.g. cellulitis) - hotter than surrounding tissue
      • Skin overlying lipoma (subcutaneous fat tumors) - cooler than adjacent tissue
  • Skin turgor
    • May be used as a measure of moderate to severe hydration.
    • Pinch a small area of skin between index finger and thumb. Hold firmly for 2-3 s and then release.
    • Healthy, well-hydrated skin immediately springs back into its resting position.
    • In significant dehydration, when skin elastic tissue is lost (e.g. aging) - behaves like putty, slowly reshapes to its resting position.
  • Skin edema
    • Press thumb or fingers into the skin, maintain pressure for a short time, then release.
    • Thumb or finger impression remains indented if excessive fluid ('pitting' edema).
  • Examination Summary - Hair
    • Inspection
      • Assess color, distribution, quanitity
      • Note loss, inflammation, scarring
    • Palpation
      • Texture
  • Examination Summary - Nails
    • Inspection Note color, length, configuration, base angle, symmetry
    • Observe folds for signs of infection, warts, cysts, tumors Palpation, measurement Squeeze nail to test adherence.
  • Examination Summary - Skin
    • Inspection
      • Insure adequate lighting
      • Assess contour, symmetry, color
      • View exposed & unexposed areas
    • Palpation
      • Feel for moisture, temperature, texture, turgor, mobility
      • Use dorsum to palpate temperature
    • Transillumination
      • View cysts, masses
  • Common Skin Lesions
    • Some lesions are readily recognizable
    • Regardless you must obtain hx, assess, describe.
  • Acne Vulgaris
    • Common disorder pilosebaceous unit occurs at puberty.
    • Predispose: plugging of duct, increased sebum production, bacterial growth, hormonal changes
    • Presents with greasy skin, blackheads (comedones), papules, pustules, scars.
    • Common, varying severity, affects face, chest, back.
    • Usually subsides in third decade.
  • Examples
  • Drug Reactions
    • Dx probably most common cause of acute skin disease
    • Must include complete hx all Rx exposures over preceding month.
    • Common antibiotics Rx rash - ampicillin, penicillin, sulfonamides
    • It may be difficult to distinguish between Rx reaction and dz under tx. In addition, drug reaction may closely mimic skin diseases.
    • With > one Rx difficult to identify offending agent.
  • Drug Reactions
    • Rx may cause 2ndary skin eruptions
      • Broad-spectrum antibiotics may encourage growth of candida - can present as a 'drug-related' skin rash.
    • Reactions may manifest within min-hrs of Rx or delays > 2 wks (post Rx dcÕd - ampicillin). Different expressions of drug sensitivity
  • Toxic Erythema
    • Profuse eruptions affect most of body
    • Red macules appear, overlap, coalesce = appearance diffuse erythema
    • Erythematous skin desquamates as it heals.
    • Most often caused by ampicillin also sulfonamides (including cotrimoxazole), phenobarbitone, infections.
  • Exfoliative Dermatitis
    • Name erythroderma. Form of dermatitis
    • Diffuse erythema, desquamation of epithelium.
    • Severe - pt may lose both heat, fluids.
    • Many Rx implicated. Barbiturates, sulfonamides, streptomycin, gold predominant.
  • Urticaria
    • Intense itching, localized swellings of skin, may occur anywhere.
    • Typically, wheals - red at margin, paler centers.
    • Characteristic - tendency to disappear within a few hours.
  • Angioedema
    • Usually associated with urticaria.
    • Characterized by swelling of face, hands.
  • Erythema Nodosum
    • Symmetrical distribution
    • Acute crops of painful, tender, raised red nodules
    • Usually affect extensor surfaces (shins; also thighs, upper arms
    • Over 7-10d, color change from bright red to purples to yellowish discoloration.
    • Caused by vasculitis, may be recurrent
    • Most commonly with sulfonamides, OCÕs, barbiturates.
  • Erythema Multiforme
    • Symmetrical, round (annular) lesions; esp hands/feet - may extend more proximal.
    • Central blistering may occur - 'target' lesions..
    • With drugs, vaccination, herpes simplex.
    • Bullae in severe form.
    • With drugs, vaccination, herpes simplex infection.
  • Stevens-Johnson Syndrome
    • Form of erythema multiforme - severe blistering, ulceration affects mucous membranes of mouth; often eyes, nasal, genital mucosa.
  • Photosensitive Drug Rashes
    • Occurs in sun-exposed areas (face, necklace region, extensor surfaces of limbs).
    • May appear as erythema, edema, blistering or an eczematous rash.
  • Eczema
    • Common abnormality caused by different mechanisms.
    • Dz may be acute, subacute, chronic - all may co-exist. Itching major sympt. Acute characterized by edema, vesicle formation Exudation (weeping) , crusting. Chronic eczema - dry, scaly, hyperkeratotic patches and thickening and fissuring of the skin.
  • Seborrheic Dermatitis
    • Eczematous condition occurring in infants, adolescents, young adults.
    • Erythema, scaling with symmetrical rash. May get 2ndary infection
    • Scalp most common, central face, eyelid margins, nasolabial folds, cheeks, eyebrows, forehead.
  • Psoriasis
    • Well-defined, slightly raised, erythematous.
    • Chronic phase, silvery scales cover the surface.
    • Vary in size from small (guttate) to large plaques.
    • Guttate (1-3 cm) lesions widely distributed, may resolve or persist as chronic psoriasis.
  • Trauma

MACurran 09/28/00