chap 19 - disorders of the skin Flashcards by Amelia McRoberts

function of the skin

protection
- melanocytes
- nerves and sensory receptors
- hair
- nails
- temp regulation

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melanocytes

secrete melanin, filters ultraviolet ligjt

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nerves and sensory receptors

perceive cold, heat, pressure, and pain

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hair

filters dust and debris

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nails

protect the ends of the fingers and toes

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the skin is made of several layers

epidermis, dermis, hypodermis
- accessory organs

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epidermis

outermost layer

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dermis

connective tissue, contains sweat glands and blood vessels, hair follicles
- sensory receptors

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hypodermis

adipose tissue

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epidermis layers

deep to most superficial
- Stratum Basale (mitotic) (bottom layer) - stem cells
- Keratinocytes = epithelial cells that is packed with protein keratin, which waterproofs the skin
- Melanocytes = making melanin
- Langerhans cells = specialized macrophages that live in the skin
- Stratum spinosum - prickly, little spines
- Stratum granulosum
- Stratum lucidum
- Only in palms and soles of feet
- Stratum corneum (dead cells filled with keratin, lost as skin in rubbed)
Turnover = 28 days

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structure of the dermis

Responsible for strength of skin
Structure
Contains
- Blood vessels
- Lymphatics
- Hair follicles
- Sweat glands
Ground substance
- Connective tissue protein
- Elastin
- collagen

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most frequent and serious problems

Cuts and abscesses
Lesions
- Acne, nevi, and warts
Eczematous dermatitis
Seborrheic dermatitis (dandruff)
Rashes
Actinic or solar keratoses = age spots
Skin cancer

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signs and symptoms

Pruritus = itchiness
Changes in texture, appearance
Pain
Exanthem
- Rash (widespread)

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tests

biopsy

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general conditions of skin

Skin color may be a sign of disease
What contributes to skin color?
- Pigmentation
- Blood flow = capillary dilation, inflammation, injury, amount of hemoglobin, oxygenation of blood, substances in blood (bilirubin)
Examples of disorders which lead to skin color changes
- Pregnancy
- Stretch marks - rapid rate of cell division
- Melasma - has to do with the hormones that are going up and changing
- Blood lipid abnormalities - skin xanthoma - deposition of cholesterol
- Diabetic ulcer = lesion (a lot of times on the foot) blood flow is reduced, decreased immune system, neuropathy of extremities – sore gets bigger and bigger
- Autoimmune disease - SLE

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lesions

infections, infestations, bites
- Bacteria or virus
- Impetigo
- Acne
- Virus
- Warts
- Insects, mites, scabies

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lesions: viral disorders

varicella zoster virus, warts, impetigo

varicella zoster virus

Chicken pox - sneaky – hides in the neurons so the immune system can’t see it and this is how it can become shingles in later life
Shingles - typically in one half of the body due to the neurons that the chicken pox hid in
Can lie dormant
Signs and symptoms
Painful vesicles

warts

More common on feet and hands
Etiology
More than 100 different strains of HPV
Contagious via direct contact
Signs and symptoms
Appearance varies depending on the type of virus and the location involved
Treatment = freeze them off → but they can come back, cut it out

impetigo

Etiology
Bacteria: streptococci or staphylococcus
Contagious = spread by direct contact with secretions
Signs and symptoms
Fluid-filled, itchy vesicles face
Vesicles enlarge, rupture, then crust over
Treatment? Antibiotics
Predisposing factors = stress = it is an opportunistic infection

fungal disorders

dermatophytosis, tinea

dermatophytosis

fungus metabolizing keratin
Skin, nails, hair
Superficial
Located in epidermis

tinea

Ringworm
Contagious
Thrives in warm, moist area, injured skin more vulnerable
signs and symptoms
Red, raised, scaly, pruritic lesions
Tinea Corporis
Circular lesions
Tinea capitis = scalp, losing parts of your hair
Tinea Unguium
Discolored, thickened, and softened nails
Tinea pedis = feet
Cracking, peeling, skin
Treatment = antifungal - usually start out with topical, may move to oral

acne

Characterized by presence of
Comedones (blackheads and whiteheads)
Basic lesion of acne
Multiple recurrent crops of pustules on the face, neck, and upper back during puberty and early adulthood
Hair follicles and associated sebaceous gland ducts become plugged with lipid and keratin
Become colonized by propionibacterium acnes
Blocked duct eventually ruptures
Precipitates acute inflammatory reaction
Treatment may include:
Topical or oral antibiotics
Topical or oral retinoid drugs
Accutane - vitamin A derivative, increases the turnover so the ducts don’t clog up
Steroids
To reduce inflammation

dermatitis

Generic term to describe variety of skin conditions, characterized by inflammation Acute or chronic Caused by various stimuli Atopic (eczema) Contact - Poison ivy - Metals Seborrheic Urticaria = hives Psoriasis

atopic dermatitis

Eczema Multifactorial disease with genetic basis influenced by environmental factors Most common in individuals having other manifestations of atopy (allergy) Characterized by severe itching

psoriasis

Chronic inflammatory disease of skin with a multifactorial basis Characterized by thickened areas of skin with silver-colored scales Treatment with anti-inflammatory ointments, UVB light, and systemic immunosuppressants

disorders of pigmentation

Vitiligo and albinism(autosomal recessive) are diseases of depigmentation Freckle and lentigo are non neoplastic pigmentary lesions Freckle = increased sensitivity of melanocytes Number normal Lentigo = hyperplasia of melanocytes Melanocytic nevi are benign tumors of melanocytes

melanocytic nevus

Mole Caused by benign proliferation of melanocytes Small macules or papules Varying shades of brown More common in fair-skinned individuals Majority are harmless Can become malignant Should be watched by ABCDE

skin cancer

Basal cell carcinoma Melanoma Squamous cell carcinoma

basal cell carcinoma

Occur in basal cell Occurs most frequently in sun exposed areas Rarely metastasized Appearance Pink growth Red patch Shiny bump Bleeding If allowed to grow?

squamous cell carcinoma

Proliferation of upper layers of skin (not basal) Greater risk of metastasizing than basal Symptoms Sore that doesn't’ heal

melanoma

Most dangerous skin cancer Neoplasm of melanocytes Metastasizes early Does Not respond well to chemotherapy Occurs more common in areas of sun exposure More common in children with blistering sunburns Vs cumulative exposure Can also occur in places other than skin

alopecia

abnormal hair loss

alopecia areata

autoimmune disease resulting in patchy hair loss - irreversible

senscent alopecia

age associated hair loss

androgenic alopecia

male pattern baldness, hormones, genetic predispostion

photoaging

extrinsic aging characterized by - fine coarse wrinkles, sagging, telangiectasia, rough skin texture, irregular hyperpigmentation - a lot of this happens due to changes in dermis and loss of muscle and fat mass main cause is UVR -UVA and UVB

UVA

penetrate deeper into dermis, promotes tanning, photagining

UVB

epidermis and upper dermis, sunburn, DNA damage - photocarcinogenesis

majority of skin related changes are due to alterations in the

dermis - decrease number and function of fibroblasts = important for making collagen and elastin

skin failure occurs with

extensive, severe burns types: 1,2,3 - fluid loss and infection become life-threatening emergencies