chap 19 - disorders of the skin Flashcards
function of the skin
protection
- melanocytes
- nerves and sensory receptors
- hair
- nails
- temp regulation
melanocytes
secrete melanin, filters ultraviolet ligjt
nerves and sensory receptors
perceive cold, heat, pressure, and pain
hair
filters dust and debris
nails
protect the ends of the fingers and toes
the skin is made of several layers
epidermis, dermis, hypodermis
- accessory organs
epidermis
outermost layer
dermis
connective tissue, contains sweat glands and blood vessels, hair follicles
- sensory receptors
hypodermis
adipose tissue
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
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
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
signs and symptoms
Pruritus = itchiness
Changes in texture, appearance
Pain
Exanthem
- Rash (widespread)
tests
biopsy
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
lesions
infections, infestations, bites
- Bacteria or virus
- Impetigo
- Acne
- Virus
- Warts
- Insects, mites, scabies
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
