Chapter 8 Skin Disorders Copyright 2019 by Elsevier

Functions of the Skin Acts as first line of defense Ø When unbroken Prevents excessive fluid loss Controls body temperature Cutaneous vasodilation Ø Secretion and evaporation of sweat Ø Active in sensory perception Ø Important as defense against environmental hazards Synthesizes vitamin D Ø On exposure to small amount of ultraviolet light Copyright © 2019 by Elsevier Inc. All rights reserved. 2

Review of Normal Skin Layers of the skin Epidermis—avascular Ø Dermis Ø Subcutaneous tissue

Epidermis Five layers—vary in thickness Keratin Ø Melanin Ø Lack of melatonin production Vitiligo Ø Skin pigment—determines skin color • Production depends on multiple genes and environment. Albinism Ø Waterproofing of the skin Small areas of hypopigmentation Melasma Ø Patches of darker skin Copyright © 2019 by Elsevier Inc. All rights reserved. 4

Layers of the Epidermis Stratum basale Ø Mitotic activity Stratum spinosum Cells connected by desmosomes Ø Protein synthesis Ø Stratum granulosum Ø Keratin formation begins Stratum lucidum Stratum corneum Ø Waterproofing barrier Copyright © 2019 by Elsevier Inc. All rights reserved. 5

Dermis Connective tissue Ø Contains elastic and collagen fibers Flexibility and strength of the skin Contains nerves and blood vessels Ø Includes sensory receptors for: • Pressure • Touch • Pain • Heat • Cold Copyright © 2019 by Elsevier Inc. All rights reserved. 6

Appendages of the Skin Hair follicles Ø Sebaceous glands Ø Stratum basale—hair-producing • Arrector pili muscle associated with hair follicle Produce sebum • Secretion increases at puberty—influence of sex hormones. Sweat glands Eccrine—all over body Ø Apocrine • Axillae, scalp, face, external genitalia Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 7

Hypodermis Beneath dermis Connective tissue Ø Fat cells Ø Macrophages Ø Fibroblasts Ø Larger

Diagram of the Skin Copyright © 2019 by Elsevier Inc. All rights reserved. 9

Resident (Normal) Flora of the Skin Mixed flora—components differ in various areas of the body. Microbes also reside under the fingernails, in hair follicles, and in glands. Opportunistic infections may occur because of injury or other inflammatory lesion. Infection may spread systemically from skin lesions. Copyright © 2019 by Elsevier Inc. All rights reserved. 10

Skin Lesions The physical appearance of the lesion is necessary to make a diagnosis. Skin lesions may be caused by: Systemic disorders • Liver disease Ø Systemic infections • Chickenpox Ø Allergies to ingested food or drugs Ø Localized factors • Include exposure to toxins Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 11

Skin Lesions (Cont. ) Types of lesions Location Ø Length of time lesion has been present. Ø Changes occurring over time Ø Physical appearance • Color • Elevation • Texture • Type of exudate Ø Presence of pain or pruritus (itching) Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 12

Common Skin Lesions Copyright © 2019 by Elsevier Inc. All rights reserved. 13

Common Skin Lesions (Cont. ) Copyright © 2019 by Elsevier Inc. All rights reserved.

Copyright © 2019 by Elsevier Inc. All rights reserved. 15

Pruritus Associated with Allergic responses Ø Chemical irritation caused by insect bites Ø Infestations by parasites (e. g. , scabies) Ø Mechanism not totally understood Release of histamine in a hypersensitivity response causes marked pruritus. Ø Infection may result from breaking the skin barrier. Ø Caused by scratching Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 16

Diagnostic Tests for Skin Lesions Culture and staining of specimens Bacterial infections: microscopic and direct observations Ø Specific procedures for fungal or parasitic infections Ø Biopsy Ø Blood tests Ø Detection of malignant changes • Safeguard prior to or following removal of skin lesions Helpful in diagnosis of conditions caused by allergy or abnormal immune reaction Skin testing using patch or scratch method Copyright © 2019 by Elsevier Inc. All rights reserved. 17

General Treatment Measures Pruritus Topical agents to reduce sensation Ø May be treated by antihistamines or glucocorticoids Ø Avoidance of allergens Ø Infections Ø Reduce risk of recurrence May require antibiotic treatment Precancerous lesions Ø Surgery, laser therapy, electrodessication, cryosurgery Copyright © 2019 by Elsevier Inc. All rights reserved. 18

Skin Inflammatory Disorders Copyright © 2019 by Elsevier Inc. All rights reserved. 19

Contact Dermatitis Exposure to an allergen Metals, cosmetics, soaps, chemicals, plants Ø Sensitization occurs on first exposure. Ø Pruritic rash develops at site a few hours after exposure. Ø Direct chemical or mechanical irritation Does not involve immune response Ø Is inflammatory because of direct exposure • Removal of irritant • Reduction of inflammation with topical glucocorticoids Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 20

Pathophysiology Sensitization occurs on first exposure. Subsequent exposure results in manifestations Ø that is, pruritic rash. Location of lesions is clue to identity of the allergen Ø that is, poison ivy. Copyright © 2019 by Elsevier Inc. All rights reserved. 21

Contact Dermatitis from Adhesive Tape Copyright © 2019 by Elsevier Inc. All rights reserved.

Signs and Symptoms Allergic Dermatitis Pruritic area Erythematous area Edematous area Area often covered

Manifestations Chemical Irritation Edematous area Erythematous area May be pruritic or painful Copyright ©

Treatment Removal of irritant Topical glucocorticoids Copyright © 2019 by Elsevier Inc. All rights

Urticaria (Hives) Copyright © 2019 by Elsevier Inc. All rights reserved. 26

Pathophysiology Result of type I hypersensitivity Ø Ingestion of substances • Examples: shellfish, drugs,

Signs and Symptoms Eruption of hard, raised, erythematous lesion Lesions are highly pruritic. Found Skin Ø May be scattered all over body Ø Occasionally in pharyngeal mucosa • Airway obstruction Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 28

Urticaria (Hives) Copyright © 2019 by Elsevier Inc. All rights reserved. 29

Treatment Over-the-counter antihistamines Corticosteroids Ø With inflammation of the airways Omalizumab For chronic cases Ø Children above age 12 Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 30

Atopic Dermatitis (Eczema) Atopic—inherited tendency Common problem in infancy Rash is erythematous, with serous exudate. Ø Commonly occurs on face, chest, and shoulders Ø In adults, rash is dry, scaly, and pruritic, often on flexor surfaces. Copyright © 2019 by Elsevier Inc. All rights reserved. 31

Pathophysiology Chronic inflammation results from response to allergens. Ø Eosinophilia and increased serum Ig. E levels Affected areas become sensitive to irritants: Soaps Ø Certain fabrics Ø Temperature changes Ø Potential complication Ø Secondary infections • Due to scratching Copyright © 2019 by Elsevier Inc. All rights reserved. 32

Infant with Extensive Atopic Dermatitis Copyright © 2019 by Elsevier Inc. All rights reserved.

Treatment Elimination of aggravating agent Topical glucocorticoids Antihistamines Copyright © 2019 by Elsevier Inc.

Psoriasis Chronic inflammatory skin disorder Affects 1% to 3% of the population Believed to

Pathophysiology Onset usually in the teenage years Marked by remission and exacerbations Cases vary in severity Results from abnormal T cell activation. Excessive proliferation of keratinocytes Ø Cellular proliferation is greatly increased leading to thickening of the dermis and epidermis. Ø Shedding occurs in one day rather than two week intervals. Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 36

Signs and Symptoms Red patches of skin covered with silvery scales Small scaling spots (commonly seen in children) Dry, cracked skin that may bleed Itching, burning, or soreness Thickened, pitted, or ridged nails Swollen and stiff joints Copyright © 2019 by Elsevier Inc. All rights reserved. 37

Treatment Glucocorticoids Tar preparations Antimetabolic methotrexate Ø In severe cases Exposure to sunlight is

Psoriasis: Acute Inflammatory Stage Copyright © 2019 by Elsevier Inc. All rights reserved. 39

Pemphigus Autoimmune disorder Mainly two forms Pemphigus vulgaris Ø Pemphigus foliaceous Ø Severity varies

Pathophysiology Autoantibodies disrupt cohesion between epidermal cells. Causes blisters (bullae) to form Ø Skin sheds, leaving area painful and open to secondary infection. Ø May be life-threatening if extensive (e. g. , Stevens. Johnson syndrome) Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 41

Signs and Symptoms Blisters in mouth Blisters spreading to the skin Blisters are painful but not pruritic. Breathing difficulty due to swollen mouth and throat Copyright © 2019 by Elsevier Inc. All rights reserved. 42

Treatment Systemic glucocorticoids and immunosuppressants Copyright © 2019 by Elsevier Inc. All rights reserved.

Scleroderma May occur as skin disorder May be systemic and affect viscera Primary cause

Pathophysiology Increased collagen deposition Inflammation and fibrosis with decreased capillary networks May cause renal failure, intestinal obstruction, respiratory failure caused by distortion of tissues Copyright © 2019 by Elsevier Inc. All rights reserved. 45

Signs and Symptoms Hard, shiny, tight, immovable areas of skin Fingertips narrowed and shortened Ø Facial expression is lost Ø Raynaud phenomenon may be present. Skin tightens; movement of the mouth and eyes may be impaired. The cutaneous form may also affect the microcirculation of various organs, eventually causing renal failure, intestinal obstruction, or respiratory failure due to pulmonary hypertension. Copyright © 2019 by Elsevier Inc. All rights reserved. 46

Treatment Medications vary significantly. Based on specific manifestations Copyright © 2019 by Elsevier Inc.

Scleroderma Copyright © 2019 by Elsevier Inc. All rights reserved. 48

Skin Infections Copyright © 2019 by Elsevier Inc. All rights reserved. 49

Skin Infections May be caused by bacteria, viruses, fungi, other types of microbes, parasites Caused by opportunistic microbes Minor abrasions or cuts Serious infections may develop. Causative organism needs to be identified for appropriate treatment. Copyright © 2019 by Elsevier Inc. All rights reserved. 50

Bacterial Infections Common on the skin Primary Ø Often caused by resident flora Secondary

Cellulitis (erysipelas) Infection of the dermis and subcutaneous tissue Usually secondary to an injury Causative organism Usually Staphylococcus aureus Ø Sometimes Streptococcus Ø Frequently in lower trunks and legs • Especially in individuals with restricted circulation in the Ø extremities; also in immunocompromised individuals • Area becomes red, swollen, and painful. • Red streaks may develop, running along lymph vessels proximal to infected area. Copyright © 2019 by Elsevier Inc. All rights reserved. 52

Signs and Symptoms Reddened area Edematous (swollen) Pain Red streaks along the lymph vessels

Furuncles (Boils) Usually caused by S. aureus Begins at hair follicles Face, neck, back Frequently drains large amounts of purulent exudate Auto in Autoinoculation Ø Squeezing boils can result in spread of infection to other areas of the skin. Copyright © 2019 by Elsevier Inc. All rights reserved. 54

Signs and Symptoms Firm, red lesion Painful nodule which often develops into a large, painful abscess Abscess produces large amounts of purulent exudate (pus). Carbuncles Ø Collection of furuncles that coalesce to form a large infected mass Copyright © 2019 by Elsevier Inc. All rights reserved. 55

Treatment Compresses Ø Analgesics Ø Promote drainage Provide pain relief from inflammation Cut and

Furuncle Copyright © 2019 by Elsevier Inc. All rights reserved. 57

Impetigo Common infection in infants and children May also occur in adults Ø S. aureus—highly contagious in neonates Ø Lesions commonly on face Transmission may occur through close physical contact or through fomites. Pruritus common Ø Leads to scratching and further spread of infection Copyright © 2019 by Elsevier Inc. All rights reserved. 58

Signs and Symptoms Small red vesicles, which rapidly enlarge Vesicles rupture forming yellowish-brown crusty masses Additional vesicles develop around the primary site by autoinoculation with hands, towels, or clothes. Pruritus is common, leading to scratching and further spread of infection. Copyright © 2019 by Elsevier Inc. All rights reserved. 59

Treatment Topical antibiotics in early stages Systemic administration if lesions are extensive Ø Antibiotic-resistant strains of S. aureus are increasing in numbers. • Local outbreaks of infection may result. Copyright © 2019 by Elsevier Inc. All rights reserved. 60

Impetigo (Cont. ) Copyright © 2019 by Elsevier Inc. All rights reserved. 61

Acute Necrotizing Fasciitis Mixture of aerobic and anaerobic bacteria usually at site of infection Severe inflammation and tissue necrosis Usually caused by virulent strain of gram-positive, group A beta-hemolytic Streptococcus Ø Bacteria secrete toxins that break down fascia and connective tissue, causing massive tissue destruction. Ø Often a history of minor trauma or infection in the skin and subcutaneous tissue of an extremity Copyright © 2019 by Elsevier Inc. All rights reserved. 62

Signs and Symptoms Infected area appears markedly inflamed. Very painful Infected area rapidly increases

Systemic Manifestations Fever Tachycardia Hypotension Mental confusion and disorientation Possible organ failure Copyright ©

Treatment Aggressive antimicrobial therapy Fluid replacement Excision of all infected tissue High oxygen flow in hyperbaric chambers Amputation Delay in treatment greater tissue loss Ø Higher probability of mortality Systemic toxicity develops with fever, tachycardia, hypotension, mental confusion, disorientation, possible organ failure. Copyright © 2019 by Elsevier Inc. All rights reserved. 65

Leprosy (Hansen Disease) Caused by Mycobacterium leprae Chronic disease classified into three major types Clinical signs and symptoms vary. Generally affects skin, mucous membranes, and peripheral nerves Ø Damage can lead to loss of limbs. Ø Mechanism of pathogenicity largely unknown Diagnosis through microscopic examination of skin biopsy Treatment primarily with antibiotics Copyright © 2019 by Elsevier Inc. All rights reserved. 66

Viral Infections Copyright © 2019 by Elsevier Inc. All rights reserved. 67

Herpes Simplex Herpes simplex type 1 (HSV-1) Ø Herpes simplex type 2 (HSV-2)—genital herpes Both types of HSV cause similar effects. Primary infection may be asymptomatic. Ø Most common cause of cold sores or fever blisters Virus remains latent in sensory nerve ganglia. Recurrence may be triggered by: Ø Common cold, sun exposure, stress Copyright © 2019 by Elsevier Inc. All rights reserved. 68

Herpes Simplex (Cont. ) Spread by direct contact with fluid from lesion Spread of infection to others possible prior to appearance of lesions Potential complication Spread of virus to eye • Keratitis Ø Herpetic whitlow • Painful infection of the fingers Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 69

Herpes Simplex (Cont. ) Copyright © 2019 by Elsevier Inc. All rights reserved. 70

Herpes Simplex (Cont. ) Copyright © 2019 by Elsevier Inc. All rights reserved. 71

Verrucae (Warts) Human papillomavirus (HPV) types 1 to 4 Ø Frequently develop in children and young adults Plantar warts are common. Spreads by viral shedding of the skin surface May resolve spontaneously with time Genital warts (HPV types 6 and 11) Copyright © 2019 by Elsevier Inc. All rights reserved. 72

Plantar Warts Copyright © 2019 by Elsevier Inc. All rights reserved. 73

Fungal Infections (Mycoses) Most are superficial Candida infection is associated with diabetes. Ø May spread systemically in immunocompromised individuals Ø Diagnosed from skin scrapings Become fluorescent in ultraviolet light Ø Microscopic examination Ø Culturing of samples Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 74

Tinea capitis Infection of the scalp Ø Common in school-age children Ø Erythema may be apparent. Ø Oral antifungal medication Ø Tinea corporis Infection of the body, particularly of nonhairy parts Ø Round lesion with clear center (ringworm) Ø Pruritus may be present. Ø Topical antifungal medication Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 75

Tinea Corporis Copyright © 2019 by Elsevier Inc. All rights reserved. 76

Tinea Capitis Copyright © 2019 by Elsevier Inc. All rights reserved. 77

Tinea (Cont. ) Tinea pedis Athlete’s foot—involves the feet, particularly the toes. Ø Associated with swimming pools and gymnasiums Ø May be part of normal flora that becomes opportunistic Ø Secondary bacterial infection may occur. Ø Topical antifungal medication Ø Tinea unguium Ø Infection of the nails, particularly the toenails • Nails turn white, then brown. • Nail thickens and cracks. • Infection tends to spread to other nails. Copyright © 2019 by Elsevier Inc. All rights reserved. 78

Tinea Pedis Copyright © 2019 by Elsevier Inc. All rights reserved. 79

Other Infections Scabies Invasion by mite Sarcoptes scabiei Ø Female burrows into epidermis • Lays eggs over a period of several weeks Ø Male dies after fertilizing the female. Ø Female dies after laying the eggs. Ø Larvae migrate to skin surface. • Burrow into skin in search of nutrients • Intensively pruritic! Ø Larvae mature and cycle is repeated. Ø Burrows appear on skin as tiny, light brown lines. Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 80

Scabies Copyright © 2019 by Elsevier Inc. All rights reserved. 81

Other Infections (Cont. ) Pediculosis (lice) Pediculus humanus corporis—body louse Ø Pediculus humanus capitis—head louse Ø Pediculus humanus pubis—pubic louse Ø Female lice lay eggs on hair shafts. Ø After hatching, louse bites human host, sucking blood for production of ova Ø Excoriations result from scratching. Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 82

Pediculus Humanus Capitus Copyright © 2019 by Elsevier Inc. All rights reserved. 83

Lice in Hair Copyright © 2019 by Elsevier Inc. All rights reserved. 84

Skin Tumors Copyright © 2019 by Elsevier Inc. All rights reserved. 85

Keratoses Benign lesions are usually associated with aging or skin damage. Seborrheic keratoses Ø Proliferation of basal cells • Lead to oval elevation • May be smooth or rough Actinic keratoses On skin exposed to ultraviolet radiation Ø Commonly in fair-skinned persons Ø Lesion appears as pigmented, scaly patch Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 86

Warning Signs of Skin Cancer A sore that does not heal A change in shape, size, color, or texture of a lesion, especially an expanding, irregular circumference or surface New moles or odd-shaped lesions that develop A skin lesion that bleeds repeatedly, oozes fluid, or itches Copyright © 2019 by Elsevier Inc. All rights reserved. 87

Guidelines to Reduce Risk of Skin Cancers Reducing sun exposure at midday and early afternoon Covering up with clothing Remaining in shade Ø Wearing broad-brimmed hats to protect face and neck Ø Applying sunscreen or sunblock Protecting infants and children from exposure and sun damage to skin Copyright © 2019 by Elsevier Inc. All rights reserved. 88

Squamous Cell Carcinoma Painless, malignant tumor of the epidermis Lesions most commonly found on exposed areas of the skin but also in oral cavity Face and neck Ø Base of tongue Ø Excellent prognosis when lesion is removed within reasonable time Invasive type arises from premalignant condition. Copyright © 2019 by Elsevier Inc. All rights reserved. 89

Squamous Cell Carcinoma (Cont. ) Copyright © 2019 by Elsevier Inc. All rights reserved.

Malignant Melanoma Highly metastatic form of skin cancer Develops in melanocytes Ø From a nevus (mole) Often appear as multicolored lesion with irregular border Grow quickly Ø Change in shape, color, size, texture Ø May bleed Ø Treatment: surgical removal and radiation plus chemotherapy Copyright © 2019 by Elsevier Inc. All rights reserved. 91

Squamous Cell Carcinoma (Sun-Exposed Ear) Copyright © 2019 by Elsevier Inc. All rights reserved.

The ABCD of Melanoma is suspected in any nevus that shows change in appearance. Ø change in border. Ø change in color. Ø increase in diameter. Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 93

Malignant Melanoma (Cont. ) Copyright © 2019 by Elsevier Inc. All rights reserved. 94

Kaposi Sarcoma Occurs in those with AIDS and other immunodeficiencies May affect viscera as well as skin Malignant cells arise from endothelium in small blood vessels. Purplish macules Ø Nonpruritic, nonpainful Ø In immunocompromised patients, lesions develop rapidly over upper body. Combination of radiation, chemotherapy, surgery, biological therapy Copyright © 2019 by Elsevier Inc. All rights reserved. 95