Week 10-the Skin Flashcards
What is the skin
Largest organ
Up to 7 layers
Protective barrier
Prevents loss of moisture
Reduces harmful effects of UV radiation
A sensory organ
Temperature regulation
Metabolic functions
What is the epidermis
Outermost layer
5 regions
Waterproof, protective barrier
Made up of stratified squamous epithelial
What is dermis
Consists of epithelial tissue
Nerve endings, hair follicles, sweat, sebaceous and apocrine gland, lymph and blood vessels
What is the subcutaneous fatty tissue
Attaches skin to underlining bone and muscle
Supplies w blood vessels and nerves
Consists of lose ct, adipose tissue and elastin
Main cell types are fibroblasts, macrophages, adiopctes
What is vitiligo
Disorders of pigmentation
Hypopigmentation: vitiligo
Chronic depigmentation skin disorder
1-2% people
1/3 in childhood
Autoimmune t-cell mediated destruction of melanocytes
Asymptomatic symmetrical well-demarcated maculae’s of complete pigment loss
Affects face, genetalia and bony prominences
List acute inflammations
Urticaria- allergic/heat rash
Acute eczema- triad with asthma and hay fever
25% children have eczema
Lichen sclerosis- eczma for a while, thicker white spots
Erythema multiforme- patches of rashes
What is urticaria (hives)
Type 1 sensitivity
Short lived, itchy swelling
Erythematous plaques and papules
Caused by infections, drugs, allergens and physical triggers (friction, sweating)
Usually on trunk or extremities
Antibody- mast cell degranulation- inflammation
Describe acute eczema
eczema
• Greek “to boil over”
• 3 types:
1. Allergic contact dermatitis
2. atopic dermatitis
3. Drug-related eczematous dermatitis
• Type IV hypersensitivity
Initial exposure to antigen:
Antigen processed by Langerhans cells
and presented to T cells in lymph node;
T-cell activation & memory cells
Re-exposure to antigen:
Quick (memory T-cells) response leads
to inflammation, urticaria, erythema, wet
eczema
Persistence of antigen stimulation
Chronic Inflammation
Acanthosis, hyperkeratosis
(lic
What is a strawberry haemangioma
A skin birth mark that is Jon-cancerous tumours which will eventually fade
What is Mongolian blue spot
A birth mark on mixed race babies
Sacral region
3-5 mark disappears
Dermal melanocytosis
What is erythema multiforme
Self-limited hypersensitivity reaction to:
• Infections: Herpes simplex, mycoplasm
• Drug exposure: Penicillin, antimalarials
• Cancer: Carcinoma, lymphoma
• Collagen vascular diseases: SLE, dermatomyositis
Multiple forms; macules, papules, vesicles, bullae
Red bullseye look
List chronic inflammation
Chronic eczma
Psorariasis
Lichen planus
What is psoriasis
Multifactorial: genetic & Immune
• Strong association to HLA-C
• Sensitized T-cells infiltrate the skin and secrete cytokines and
growth factors
Inflammation
Increased cell turnover
Vascular proliferation and angiogenesis
• Multisystem disorder:
- Arthritis, Myopathy, enteropathy, immunodeficiency
S&S
Chronic, real urgent
Afffectimg elbows, knees, scalp, lumbosacral, interglteal cleft and glans penis
Demarcated salmon coloured plaque loosely covering body. Silver-white scale
Often in hair line
Nail changes in 30%.
What is lichen planus
6 P’s
Pruritic (itchy), purple, polygonal, planar, papules, plaques
1/100 people
F>M
40
Resolves itself 1-2 years
Patho genesis is unknown
S
Oral lesions
Gingivitis (mouth ulcers)
Persistent ulcers
What is impetigo
Superficial Bacterial infection
Highly contagious
Frequently seen in health children
Exposes skin
Oozing blister, serous exudate, scale crust (scab)
