The Skin, hair and nails, By: Kareema Ameene Husein Al-Khafaji M.B.Ch.B., D.V.D., MSc. University of Babylon, College of Medicine. Printed on Microsoft word Introduction The skin is the largest organ of the human body, it covers an area of approximately 2m² and weights 4kg, it is not as usually supposed merely an external covering, but a complex structure, sophisticated vital organ consisting of a number of layers and tissue component ( fig.1,2,3),with many important functions (Box.1). Fig. 1 Fig.1.The epidermis, which functions both to protect the underlying Structures and to participate in inflammatory processes. Epidermal cells are constantly involved in the keratinization process, so that the entire normal epidermis is replaced approximately every 28 days and the spent stratum corneum cells are lost to the environment. 1 Fig. 2 skin with out hair (Palm or sole) Fig. 3 skin with hair 2 Box 1 Functions of the human skins Function Structure/cell involved protection against; chemical, particle horny layer ultraviolet radiation melanocytes antigens, haptens, microbes Langerhans cells Preservation of a balanced internal horny layer environment. Prevent loss of water, electrolyte horny layer and macromacules. Shock absorber dermis and subcutaneous fat Temperature regulation blood vessels + eccrine sweat glands Insulation subcutaneous fat Sensation specialized nerve endings Lubrication sebaceous glands Protection and prising nails Calorie reserve subcutaneous fat Vitamin D synthesis keratinicyte Body odour/pheromones Apocrine sweat glands Psychological display skin, lips, hair and nails Skin is a mirror of the internal body organ, its examination reflects a lot of internal diseases, so the physician must has a good knowledge in dermatology to diagnose the common skin diseases as well as the skin manifestations of internal organs such as; thyrotoxicosis, hypothyroidism, acromegaly , Addison disease, diabetes mellitus , leprosy, ulcerative colitis, internal malignancy,..etc.with naked eye, but one should suggested that “what the mind dose not know, the eyes cannot see” .So dermatology is a visual clinical specialty. The accurate diagnosis of most skin lesions requires an adequate history, careful examination of the patient preferably in a natural light, some times magnifying lens is useful and occasionally, laboratory investigations might be needed. The out line of an approach to dermatologic diagnosis: 1-Epidemiology and Etiology; Age, sex, race, occupation, address. 11-History of present skin condition; A-Duration of onset of skin lesions in: days, weeks, months, years. B-Site of onset, details of spread. C-Exacerbating factors like relation ship of skin lesions to; season, heat, cold, drug ingestion, alcohol intake, occupation, hobbies, exposure to 3 irritants, effects of mense, and pregnancy. D-Skin symptoms: itch, burning, pain, paresthesia. E-Constitutional symptoms; 1-“Acute illness” syndrome: headaches, chills, fever, weakness. 2-“Chronic illness”syndrome: fatigue, weakness, anorexia, wheight loss, malaise. F-Past history of skin disorders G-past general medical history inquires specifically about asthma and hay fever. H-Family history of skin disorders; if positive-inherited, infection/infestation. I- Family history of medical disorders. J- Drugs used to treat present skin condition; topical, systemic, physician Prescribed? , patient initiated? K- Drugs prescribed for other disorders (including those taken before onset of Skin disorder). L-Systemic review. III.Physical Examination; A-Appearance of patient; -uncomfortable, toxic, well, intelligence and educational level. -Signs of anemia, jaundice, and cyanosis. -Features of hyperlipidaemia and endocrine diseases like; acromegaly, Cushing syndrome, Addison disease, thyrotoxicosis, or hypothyroidism -Deformities, swellings, buffeness of the eyes. B-Vital signs; temperature, pulse, respiratory rate and blood pressure. C- Examination of skin in which four major skin signs should be noted: (1) type, (2) shape, (3) arrangement, (4) distribution of lesions. 1-Type of lesions (Box 2) Primary skin lesions, secondary skin lesions, special skin lesions: (Box 2) primary skin lesions Lesion definition and examples Erythema: is redness caused by vascular dilatation. Macule: non-palpable area of altered color of skin; may be red, hypopigmen, depigmented, hyperpigmented or blue. Examples; Vitiligo, melasma, Tinea versicolor. Papule: palpable elevated small area of skin (less than 0.5 cm) in diameter. It is produced by proliferation of tissue cells or infiltration with the inflammatory cells. Example lichen planus. A papule of (1-2mm.) in diameter in size is called micropapulue like keratosis pilaris.A papilloma is a nipple-like projection from the skin like filiform wart. Plaque: is an elevated area of skin greater than 2cm. in diameter but with out substantial depth .Example; psoriasis. 4 Nodule: is a solid mass in the skin, usually greater than 0.5cm. in diameter, in both width and depth, which can be seen to be elevated or can be palpated. Example boile. Tumour: is hard to be defined as the term is based more correctly on microscopic pathology than on clinical morphology. We keep it here as a convenient term to describe an enlargement of the tissues by normal or pathological material or cells that form a mass, usually more than cm. Because the word„tumour‟ can scare patients, tumour may courteously be called „large nodules‟ especially if they are not malignant, example lipoma. Vesicle: is a circumscribed elevation of skin, less than 0.5cm. and containing fluid. example; herpes simplex. Bulla: is a: is a circumscribed elevation of skin, less than .5cm. and containing fluid. example elevation of skin, more than 0.5cm. and containing fluid. example; pemphigus vulgaris. Pustule: is a circumscribed collection of leukocytes and free fluid in the skin varies in size examples: folliculitis, acne. Abscess: is a localized collection of pus in a cavity, more than 1cm in diameter. Wheal: Sudden exudation of fluid in the superficial dermis producing a flat raised area of any size and often with an orange-peel appearance on the surface; they are transient and may last only a few hours. It is a primary lesion of urticaria and can be seen in insect bits, dermographism. Angioedema: is a diffuse swelling caused by oedema extending to the subcutaneous tissue. Petechiae: are pinhead-sized macules of blood in the skin. Purpura: Circumscribed deposit of blood in the skin of more than0.5cm in diametr.Example of both Cutaneous vasculitis, senile purpura, gonococcemia. Haematoma: is a swelling from gross bleeding. Box 3.Secondary Skin lesions Secondary lesions develop during the evolutionary process of skin disease or are created by scratching or infection. They may be the only type of lesion present in which case the primary disease process must be inferred. Secondary skin lesions are: - Skin lesion Definition and examples (e.g.) Scales: excess dead epidermal cells that are produced by abnormal keratinization and shedding.e.g. Psoriasis, tinea versicolor, pityriasis rosea. Crusts: a collection of dried serum and cellular debris e.g. impetigo, atopic dermatitis (face). Erosions: A focal loss of epidermis; they do not penetrate below the dero- epidermal junction and there fore heal with out carring.e.g.Candidiasis ,intertrigo, vesiculo- bullous disease. Ulcers: A focal loss of epidermis and dermis, they heal with scarring e.g.Aphthus, chancroid, and primary chancre. 5 Fissure: A linear loss of epidermis and dermis with sharply defined, nearly vertical walls e.g. chapping (hands, feet), intertrigo, chronic eczema (fingertip). Atrophy: depression in the skin resulting from thinning of the epidermis or dermis e.g. striae. Scar: Abnormal formation of connective tissue implying dermal damage, when following injury or surgery, they are initially thick and pink but with time become white and atrophic (e.g. burn, acne). Atrophic scar remains below the surface; hypertrophic scar is raised above the surface, while a keloid grows beyond the limits of original lesion. Lichenification: A diffuse thickening of skin, hyperpingmentation and accentuation of skin lines with sever itching It is seen in:1-Neorodermatitis2-psoriasis 3-Atopic dermatitis 4-Chronic zinc deficiency. Excoriation: Scratching leading to the removal of the top of a lesion or even the skin other wise. Sinus: is a cavity or channel that permits the escape of pus or fluid. Striae: (streach mark): is a streak-like linear atrophic pink, purple or white lesion of the skin caused by changes in the connective tissue. Box 4.Special Skin Lesions: Skin lesion Definition and examples Comedone: A plug of sebaceous and keratinous material lodged in the opening of hair follicle; the follicular orifice may be dilated (black head) or narrowed or closed head (white head).It is a primary lesion of acne vulgaris. Milia: A small, superficial keratin cyst with no visible opening. Cyst: Circumscribed lesion having a wall and a lumen; the lumen may contain fluid. Burrow: A narrow, elevated, tortuous channel with some scaling caused by scabies parasite. Telangiectasia is a visible dilatation of small cutaneous blood vessels e.g.; lupus erythematosus, rosacea, xeroderma pigmentosum. Poikiloderma: is a combination of atrophy, reticulate hyperpigmentation and telangiectasia. Color of lesions or of the skin if diffuse involvement as fallows (table 1): Skin color the disease Red Erythem Hypopigmented pityriasis alba Skin colored Pla n wart Depigmented Vitiligo Violaceous Lichen