Chapter 40 & 41: Acute and Chronic Skin Disorders

1, 2, 3,

Acute skin conditions

• Bacterial or fungal infection

• Contact with offending organism or allergen

• Medications

• Possible transition to chronic skin conditions

• Pain from damage to first layer of skin 

• Immune system and intact skin protect body 

  • Impaired tissue integrity leads to immune response 

  • Immune response from allergy and inflammation can lead to lack of tissue integrity 

• Alterations in tissue perfusion can lead to damage or necrosis

Chronic skin conditions

• Long term, may or may not resolve

• Viral infection

Cellulitis

• Diffuse painful inflammation of skin and subcutaneous layers induced by a bacterial infection that enters through a break in the skin (cut, scrap, burn, surgical incision, bug bite)

• Damage at dermis 

• Clinical manifestations

  • Painful, red, swollen area of skin; hot, tender to touch

  • Fever and chills

  • Vesicles, bullae, plaques (with staphylococcus)

  • Tachycardia, hypotension, confusion, headache

  • Lymphadenitis and Lymphangitis 

Impetigo

• Bacterial infection 

• Superficial acute, highly contagious skin infection 

• Etiology and pathogenesis 

  • Colonization facilitated by high temperature, humidity, preexisting skin disorders, young age (2-5), recent antibiotic treatment 

Furuncle

• Bacterial infection 

• Extension of folliculitis or infection of sebaceous gland

• Spreads down hair shaft through follicle and into dermis 

• a single, painful, pus-filled bump around a hair follicle

Carbuncle

• Bacterial infection 

• Cluster of infected hair follicles 

• The cluster coalesces to form lesion filled with pus, dead tissue, and fluid 

Candidiasis

• Fungal infection 

• Infection of skin or mucous membranes with any species of Candida (C. albicans most common)

  • Mouth, throat, lungs, vagina, folds of skin, bowel

  • Usually secondary condition

• Etiology and pathogenesis

  • Candida normal in skin and mucous membranes 

  • Warmth, moisture, breaks in epidermis can cause infection 

  • Life threatening if in bloodstream

Candidiasis- Clinical manifestations

• Thrush: white covering of tongue, mouth, throat

• Vaginal yeast infection: itching; foul odor; white discharge 

• Balanitis: flattened pustules, edema, burning, tenderness

• Diaper rash: dark red patches in skin folds; fluid-filled spots 

Tinea

• Contagious infection by different types of fungus 

  • Superficial infections; called dermatophytoses 

  • Named by location on body

• Tinea pedis: Athlete’s foot, which affects the feet with symptoms like itching, scaling, and blisters between the toes

• Tinea cruris: Jock itch, a rash in the groin area

• Tinea capitis: Ringworm of the scalp, cause itchy, red patches and hair loss

• Tinea corporis: Ringworm on the body, appearing as a ring-shaped rash

• Tinea versicolor: Discolored, scaly, and dry patches on the skin

Necrotizing Fasciitis

• Flesh-eating disorder

• Rapidly spreading infection caused by aerobic and anaerobic bacteria 

• Etiology and pathogenesis 

  • Starts from contagious ulcer, wound, untreated skin infection, complication of surgery, abscess

  • Occlusion of small subcutaneous vessels; tissue ischemia, infarction, necrosis 

Stevens-Johnson Syndrome

• Rare disorder of skin and mucous membrane

  • Cell death causes epidermis to separate from dermis

• Etiology 

  • Side effect for more than 200 medications 

  • Infectious causes

  • Delayed hypersensitive reaction 

• Clinical manifestations 

  • Flulike symptoms 

  • Symmetric burning rash; red, purple target lesions 

Toxic Epidermal Necrolysis (TEN)

• Inflammation of skin caused by poison

• TEN with spots

  • Widespread with detachment of epidermis, erosion

  • More than 30% of body surface area 

• TEN without spots 

  • Widespread with erythema, no lesions

  • More than 10% of body surface area 

• Etiology

  • Reactions to drugs; bacterial infection; malignancy; graft-versus-host disease; vaccinations 

• Clinical manifestations

  • Flulike symptoms

  • Rash; large blisters in center rash; ruptures; skin peels off

Chronic viral skin infections

• Examples of common causative organisms

  • Herpes simplex virus

  • Varicella-zoster virus

  • Human papillomavirus

Herpes simplex virus type 1 (HSV-1)

• Affected body regions

  • Herpes labialis: lips; cold sores)

    • Most common HSV-1 infection

  • Herpetic keratitis (eye)

  • Herpetic whitlow (digits or hands)

  • Herpetic gladiatorum (torso of wrestlers)

  • Herpetic sycosis (beard follicles)

• Usually contracted during childhood

• Recurrences persist into old age (adulthood)

Herpes simplex virus type 2 (HSV-2)

• Causes most sexually-transmitted anogenital herpes 

  • Lesions on genitals, perineum, or anus, any opening at genitals

• May cause cold sores

  • Less common cause than HSV-1

• Likely to be contracted via sexually contact

  • Typically in adolescence or young adulthood 

• 5th most common U.S sexually transmitted infection 

  • 1 in 6 adolescents and adults of both genders

HSV-1 and HSV-2: Etiology and Pathogenesis

• Virus enters skin or mucous membrane via microscopic tear 

• Virus travels to sensory root ganglion 

• Virus becomes dormant and permanent resident of ganglion

• Cell-mediated immune system is triggered 

• Viral activation occurs

• Virus travels from neuron to skin innervated by neuron 

• Virus enters dermal and epidermal cells 

• Viral replication causes recurrent rash outbreak

HSV-1 and HSV-2: clinical manifestations

• May have asymptomatic herpes or mild fever 

• Usually begins with prodrome- fever or flu-like symptoms 

• Red, swollen area of skin or mucous membrane develops

• Eruption of painful vesicles 

• Regional lymph nodes swell 

• Lesions open and form painful ulcers that crust and begin healing 

• Primary genital herpes 

  • May cause dysuria and urinary retention, especially in women 

Herpes Zoster

• First VZV infection causes chickenpox

  • Each skin lesion contains viral particles 

  • Viral particles travel to other structures

    • Sensory dorsal-root ganglia or a cranial nerve

  • Viral particles become dormant for life

• Cell-mediated immunity

  • Prevents virus reactivation in the form of HZ

  • Decreases with aging

    • Increased risk for reactivation of VZV as HZ

Herpes Zoster- Potential Complications

• Postherpetic neuralgia (PHN)- most common complication

• Transient ischemic attack (TIA) and stroke 

• Encephalitis and aseptic meningitis 

• Chronic eye disorders and retinal necrosis 

• Bacterial superinfection of lesions

• Cranial or peripheral nerve palsies 

• Pneumonitis

• Hepatitis

Herpes Zoster- Diagnosis

• History and physical examination 

  • Usually sufficient for diagnosis after rash appears 

  • Atypical or recurrent rashes (more than episodes)

    • May require laboratory testing to identify cause 

• Laboratory testing 

  • Direct immunofluorescent assay 

  • PCR assay 

Warts

• Cause: Various types of human papillomavirus (HPV)

• Sties of occurrence 

  • Anywhere on skin or mucous membranes 

• Malignancy 

  • Most lesions caused by HPV are benign 

  • Some HPV types linked to dysplasia and cancer 

    • Genital HPV 

      • Most frequently occurring sexually transmitted infection in US

Warts- Pathogenesis

• HPV

  • Enters skin via small openings

  • Infects epidermal basal layer 

• Viral replication occurs in cell nuclei 

• HPV causes nuclear atypia 

  • Structural abnormality in a cell 

• Nuclear atypia triggers epidermal cell changes 

  • Replication and hyperproliferation of keratinocytes 

• Wart develops

Skin Disorders with a Genetic Basis

• Family history 

  • Most important risk factor for certain chronic skin diseases

• Several chronic skin disorders have genetic component

  • Examples

    • Atopic dermatitis 

    • Psoriasis 

    • Hidradenitis suppurativa  

Eczema- Atopic Dermatitis

• Eczema- general term

• Describes inflammatory skin disorders

• Includes atopic dermatitis

  • Most sever form of eczema

Atopic Dermatitis

• Chronic, recurring, itchy, inflammatory disorder

• Associated with increased serum IgE

• Affected individuals often have other atopic disorders

  • Ex: asthma, allergic rhinitis

• Most often affects children

• May persist into adulthood

• AD and susceptibility to infection: Dysfunctional epidermal barrier

• Clinical manifestations

  • Exacerbation and remission of dry, itchy, red skin

  • Begins in infancy

  • Constant pruritus

    • Prevailing symptoms

    • Precedes eczematous rash

  • Skin excoriations and lichenification

  • Negative impact on overall quality of life: sleep disturbances, depression

Psoriasis

• Etiology

  • Immune-mediated disease

  • Genetic and environmental causation

• Pathogenesis

  • Hyperproliferation of keratinocytes

  • Decreased epidermal cell turnover rate

  • Inflammation

  • Thickening of dermis and epidermis

• Manifestations

  • Plaque psoriasis- skin lesion usually round or oval, well-demarcated plaques

Hidradenitis Suppurativa

• Etiology

  • Genetic, immunologic, hormonal, and environmental factors

• Pathogenesis

  • Occlusion of hair follicle via infundibular hyperkeratosis

  • Hyperplasia of follicular epithelium 

  • Collection of cellular wastes 

  • Cyst forms in apocrine sweat gland adjacent to hair follicle 

  • Nodule opens beneath the skin and spreads laterally 

  • May lead to abscess formation and sinus tract formation

  • Keloid-like scarring may occur

• Manifestations

  • Painful nodules, abscesses and sinus tract formations

  • Lesions develop in skinfold area