Anatomy, histology, physiology of the skin Anatomy, histology, physiology of the skin. Methods of examination of patients with skin diseases. Morphology of primary and secondary skin lesions. Lector: Shkilna M.

Content Anatomy of skin: Functions of the skin. Epidermis Dermis Subcutis Skin appendages . Functions of the skin. Methods of examination of patients with skin diseases: Patient’s passport. Patient’s complaints. History of present illness. Life history (past history). Objective investigation (morphology of primary and secondary skin lesions). Investigations.

SKIN… the heaviest single organ of the body! Skin is the largest organ of the body, it constitutes about 16% of body weight.

Anatomy of skin Epidermis Dermis Hypodermis or subcutaneous tissue Appendages (hair, nails, sebaceous and sweat glands).

Pic: Epidermal Layers

Dermis is organized into two distinct areas: Papillary dermis (the superficial zone). Reticular dermis (the deeper zone - it composes the bulk of the dermis).

Components of the dermis: collagen (70-80%) – for resiliency; elastin (1-3%) – for elasticity; proteoglycans – to maintain water within the dermis.

Subcutis or subcutaneous fat : is arranged into distinct fat lobules which are divided by fibrous septae blood vessels, nerves, and lymphatics are also found in the fibrous septae.

(in granular cell layer). Skin vessels: Skin nerves: Superficial net (in granular cell layer). Deep plexus (in subcutaneous fat).

Appendages Eccrine sweat glands (open directly onto surface of skin and regulate body temp) Apocrine glands (axillae, nipples, areolae, anogenital area, eyelids and external ears) respond to emotional stimuli, bacteria causes body odor. Sebaceous glands (secrete sebum, keep skin/hair from drying out) stimulated by hormones Hair (Vellus and Terminal) Nails (protect distal ends of fingers/toes) Eccrine are distributed throughout the body except: lip margins, eardrums, nail beds, innner surface of the prepuce, glans penis. Apocrine glands are fewer and different in Asians/ native americans causing no odor. Sebaceous glands; sex hormones primariliary testosterone and secretory activity varies throughout the lifespan. 12

Functions of the skin: Barrier. Metabolic. Temperature regulation. Secretion. Immune surveillance. Coetaneous sensation.

Methods of examination of patients with skin diseases 1. Patient’s passport. 2. Patient’s complaints: a) skin rashes b) subjective sensation, which are connected with skin rashes: itch of the skin; burning; pain; skin weeping; dryness of the skin; feeling of a tense skin; weakness, weight loss, fever etc.

History of present illness: Possible etiology of the disease ( according patient’s mind). Duration of the disease: Acute ( < 2 month) Chronic ( > 2 month). Course of a disease. Previous treatment and effect from it. Family history: contagious diseases; hereditary diseases.

Life history (past history): Past medical history. Associated inner diseases. Occupational hazards. Allergic history. Harmful habit.

Objective investigation General state of the patient ( satisfactory or not, fever etc. ). Systems revive. Assessment of nails, hair, and mucosal surfaces, even if these are recorded as unaffected.

Objective investigation (continued) Palpation ( to diagnose): Skin elastic. Skin moistness. Subcutaneous fat. Lymphatic nodes: ( size, consistency, movable or immovable etc.).

Dermatological status: Inspection. Palpation. Scraping. Dermoscopy. Laboratory end special methods.

Inspection: Skin texture Lesions: type: primary and secondary; color: red, brawn, white; shape: round, oval, annular; arrangement: grouped (herpetiform, zoster form), disseminated (erythrodermic psoriasis).

Examination of Lesions Configuration Annular (rings) Grouped Linear Diffuse

DISTRIBUTION Distribution The term "distribution" refers to the clinical arrangement of skin lesions on the integument. localized: grouped into specific areas generalized: dispersed all over symmetric: no pattern asymmetric: pattern lacking randomness discrete: separate grouped: clustered .confluent (coalescing): smaller into larger cleavage plane: arranged along lines of skin tension 22

CONFIGURATION Configuration The term "configuration" refers to the shape of lesions. margination: sharp?can be traced with tip of a pencil, ill-defined? circinate: round, circular > arciform: partial circle annular: round or circular with CENTRAL CLEARING iris or target: bull's eye lesions, annular with central internal activity zone serpiginous: meandering gyrate: connecting arcs linear: straight zosteriform: dermatomal Miscellaneous Helpful Modifiers verrucous: wart-like ,telangiectasia: a conditional dilated capillary blood blanching: press out ,eczematoid: dermatitis- hyperkeratotic: thick ,sessile: attached directly by the pedunculated: Color: pink, red, purple (purpuric lesions do not blanch), white, tan, brown, black, grey, yellow, can be uniform or variegated Sunexposed, sites of pressure, skin folds, follicular localization purpura: a condition characterized by extravasated blood in the skin noted on examination as non-blanchable reddish pigment     23

Morphology of primary and secondary skin lesions Primary skin lesions is the initial lesion that has not been altered by trauma, manipulation (scratching, scrubbing), or natural regression over time. Types: primary lesions without cavity; primary lesions with cavity.

Primary lesions without cavity: Macula's Urtica Papule Nodule

Macula and Patch Description Circumscribed Flat Discoloration Smaller than 0.5 cm-macula Larger that 0.5 cm- patch May be brown, blue, red.

MACULE Description Circumscribed Flat Discoloration Smaller than 0.5 cm-macule Larger that 0.5 cm- patch May be brown, blue, red or hypo pigmented Inflammatory Noninflammatory TINEA VERSICOLOR

BROWN MACULE Becker's nevus. Becker's nevus. A typical lesion with macular pigmentation and hair. Becker's nevus. This lesion contains no pigmentation.

PAPULE Description an elevated solid lesion up to 0.5 cm in diameter Color varies: flesh, yellow , white, brown, red, blue or violet May become confluent May form plaques

PLAQUE Description A circumscribed, elevated, superficial, solid lesion more than 0.5cm in diameter often formed by the confluence of papules

Plaque Examples of Plaques SECONDARY SYPHYLIS PSORIASIS PLAQUE Eczema Pityriasis roseas Tinea corporis Psoriasis Syphilis

Nodule Description Circumscribed Often round Solid lesion More that 0.5 cm in diameter Larger nodule is a tumor Metastatic carcinoma of the breast.

Lipoma: nodule/tumor: circumscribed depth implied solid lesion > 1 cm Circumscribed, elevated, deeper and firm than a papule large nodules are called tumors Lipomas are single or multip, soft, round, movable against the overlying skin. Occur especially on trunk, neck , extremities, but can occur anywhere. Lipomas are composed of fat cells and a connective tissue framework. Benign, slow growing, subcutaneous skin growth. In this case, the lipoma is rather large and located in the neck region. On palpation, these are soft, nontender, and freely mobile LIPOMA BENIGN TUMOR 33

WHEAL (HIVE) Description Starts as red erythematous macules. Soon paleoedematous wheals develop Irregular, asymmetrical Velvety to touch Erythematic well defined, fades on pressure Subside within few hours without leaving any trace Dermographism positive Wheals develop along line of scratching or pressure.

Physical urticaria Cold urticaria : Reaction to cold, such as ice, cold air or water - worse with sudden change in temperature

Primary lesions with cavity: Vesicles Bulla Pustules Cyst

Vesicle Description Herpes zoster Circumscribed collection of free fluid Up to 0.5 cm in diameter Herpes zoster

A circumscribed collection Bulla formed due to fluid in the skin and fluid collection occurs at sites where the cohesion on the skin is weak: Subcorneal Intra – epidermal, due to individual keratinocytes Dermo – epidermal junction A circumscribed collection of free fluid more than 0,5 sm in diameter

PUSTULE Description Circumscribed collection of leukocytes Free fluid Varies in size Staphylococcal folliculitis

CYST A circumscribed lesion with a wall and a lumen, it may contain fluid or solid matter

Secondary skin lesions Types: Scale. Crusts. Erosions.

EROSION Description A focal loss of epidermis; erosions do not penetrate below the dermoepidermal junction; and therefore heal without scarring Toxic epidermal necrolysis

CRUST Impetigo. A thick, honey-yellow adherent crust covers the entire eroded surface. Description Is a collection of dried serum and cellular debris- a scab Examples Acute eczematous inflammation, Atopic on the face, Impetigo- golden or honey colored, Tinea capitis.

Ulcer A focal loss of epidermis and dermis, and heal with scarring Examples Decubitus Ischemic Stasis ulcers Neoplasm's

FISSURE Description Examples A linear loss of epidermis and dermis with sharply defined nearly vertical walls Examples Chapping – hands and feet Eczema on the finger tip Asteatotic eczema. Excessive washing produced this advanced case with cracking and fissures.

ATROPHY Description A depression in the skin resulting from thinning of the epidermis or dermis Lichen sclerosus et atrophicus. The epidermis is thin and atrophic and gives the appearance of wrinkled tissue paper when compressed.

Scar Description Examples An abnormal formation of connective tissue, implying dermal damage, after injury Are initially thick and pink, but become white and atrophic Examples Post surg. Burns Keloid Post any herpes Keloids on the chest and extremities are raised with a flat surface. The base is wider than the top.

EXCORIATION An erosion caused by scratching; excoriations are often linear.

LICHENIFICATION Description An area of thickened epidermis induced by scratching Skin lines are accentuated so it looks like a washboard Examples Atopic dermatitis, chronic eczematous dermatitis

LICHENIFICATION Chronic lichenified atopic dermatitis Atopic dermatitis tx with topical steroids, varying potencies, oral H1 blockers to induce fatigue and therefore less scratching by patient 50

Scales Description The may be Excess dead epidermal cells that are produced by abnormal keratinization and shedding. The may be fine, as in pityriasis; white and silvery, as in psoriasis; or large and fish-like, as in ichthyosis Dominant ichthyosis vulgaris

INVESTIGATIONS General blood analysis. General urine analysis. General laboratory investigation: General blood analysis. General urine analysis. Stool test for parasites. Examination of blood for sugar. Wasserman reaction.

INVESTIGATIONS Diagnostic Tests Skin Biopsy Culture and sensitivity (viral, bacteria, fungi) Immunofluorescence Allergy Tests Skin Scrapings Tzanck Smear Wood’s Light Examination Clinical Photographs Diascopy

EPILUMINESCENCE MICROSCOPY (DERMATOSCOPY, DERMOSCOPY) This refers to surface microscopy using an illuminated lens with oil immersion directly on to the skin's surface. The presence of oil reduces specular reflection and reduces 'errors' due to the different refractive indexes of the various superficial layers of skin.

SCRAPING Hidden scaling of the skin. Psoriatic phenomenonts. Purpura symptom. Step A: Gently scrape the lesion with a glass slide. This accentuates the silvery scales (Grattage test positive). Scrape off all the scales. Step B: As you continue to scrape the lesion, a glistening white, adherent membrane appears. Step C: On removing the membrane, punctate bleeding points become visible.

no inflammatory types of lesions In diascopy a glass slide is pressed firmly on the skin lesion. If a red lesion blanches, it implies that the red colour is secondary to blood within the vessels. By contrast, blood outside the vessels, such as that from a bruise or from vasculitis, will not blanch. In some vascular lesions with a convoluted vessel structure, however, blunt pressure from a flat surface will not empty the vessels and the corner of a glass slide needs to be gently placed on the lesion. Even then, it will not always blanch completely. Therefore, success in blanching is a more useful physical sign than failure to blanch. When pressed on to some granulomatous lesions a glass slide reveals an appearance commonly referred to as 'apple jelly nodule'. DIASCOPY A glass slide is pressed firmly on the skin lesion. If a red lesion blanches, it implies that the red colour is secondary to blood within the vessels. By contrast, blood outside the vessels, such as that from a bruise or from vasculitis, will not blanch. Success in blanching is a more useful physical sign than failure to blanch. Granulomatous lesions a glass slide reveals an appearance commonly referred to as 'apple jelly nodule'. Inflammatory or no inflammatory types of lesions

WOOD'S LIGHT This involves irradiation with a UV light source that causes normal skin, particularly dermis, to fluoresce (in the visible light range). The basis for this is that in the ultraviolet A wavebands used by Wood's light, pigmentation has a greater degree of absorption than at longer wavebands, resulting in a greater degree of difference in fluorescence between pigmented and depigmented skin. Wood's light also enhances the examination of cutaneous pigmentary abnormalities such as in patients with vitiligo, where areas of subtle depigmentation are more easily seen.

MYCOLOGY SAMPLES Coetaneous scale, nail clippings and plucked hairs can be examined by light microscopy when mounted in 20% potassium hydroxide. The keratin is dissolved, allowing fungal hyphae to be identified.

SWABS Bacterial swabs in an appropriate culture medium are sometimes useful.

PRICK TESTS Prick tests are a way of detecting coetaneous type I (immediate) hypersensitivity to various antigens such as pollen, house dust mite or dander. The skin is pricked with a dilution of the appropriate antigen solution. After 10 minutes a positive response is indicated by a weal and a flare. The weal is due to a local increase in capillary permeability and the flare a result of activation of the axon reflex.

IMMUNOFLUORESCENCE A portion of the skin biopsy can be frozen in liquid nitrogen for direct immunofluorescence (IF). This involves visualising antigens that are present in skin by identifying them with fluorescein-labelled antibodies. Similarly, indirect immunofluorescence can identify circulating antibodies in the serum by an additional step of adding the serum to a section of normal skin or other substrate. Immunofluorescence plays a major role in the diagnosis of the autoimmune bullous disorders.

ELECTRON MICROSCOPY This investigation has played an important role in the diagnosis of some of the rare blistering disorders such as epidermolysis bullosa, although the availability of a range of antibodies to basement membrane zone antigens has in part replaced it. PHOTOTESTING Phototesting involves exposing skin (often on the back) to a graded series of doses of ultraviolet radiation (UVR) of known wavelength, either on one occasion or repeatedly.

Laboratory and special methods General laboratory investigation: general blood analysis; general urine analysis; stool test for parasites; examination of blood for sugar; Wasserman reaction.

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