Lecture 1 Introduction to General Dermatology Flashcards
What’s the largest organ in the body
Skin
What type of structures does the skin contain
Adnexal structures: hair, nails, glands, sensory structures
What is the epidermis
Outer layer- 3 cell types keratinocytes (squamous cells) majority of cells. Avascular
What is the dermis
collagen and elastin matrix with mucopolysaccharide gel also fibroblasts, dermal dendritis cells and macrophages
What is the hypodermic
(subcutaneous tissue): fat energy store, insulation, fibrous bands anchor skin to fascia
What are Melanocytes
makes melanosomes (collection of melanin) excreted and phagocytoses into keratinocytes
What are Langerhans
process antigens and migrate to lymph nodes to induce an immune response. Found in epidermis
Name the layers of the epidermis
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale
What is the nail matrix
Where the nail starts to grow from
What is the hair cycle
Anagen- active goring phase
Catagen- 2-3 week phase growth stops/follicle shrink
Telogen- resting phase
What is the function of this skin
Thermoregulation Immunity Barrier Sensation Vitamin D synthesis Interpersonal Communication
Name external causes of skin disease
– Temperature, UV, chemical (allergen or irritant), infection, trauma (Dermatitis Artefacta)
– Photosensitivity- antibiotics, NSAIDs, anti-hypertensives
– Cold Injury
– Frostbite, Chilblains
– Skin Necrosis
– Cold Urticaria
Name internal causes of skin disease
– Systemic disease, genetics, drugs, infection
– Genetic- neurofibroma, Ichthyosis
– Drug reaction
– Autoimmune- Bullous Pemphigoid
What classifies as a small lesion
Less then 5mm
What is a macule
small circumscribed area (flat, discolouration)
What is a patch
larger circumscribed area (flat, discolouration)
What is a papule
small raised area
What is a plaque
large raised area
What is a vesicle
small fluid filled
What is a bulla
large fluid filled
What is a pustule
small pus filled
What is a abscess
large puss filled
What is an erosion
Loss of epidermis
What is an ulcer
loss of epidermis and dermis
What is Leukocytoclastic Vasculitis
Small blood vessels in skin that become inflamed and burst causing a purpuric rash
Cutaneous signs are useful in diagnosing conditions such as
- Erythema Nodosum (TB, pregnancy, sarcoidosis)
- Sarcoidosis
- Vasculitis
- Malignancy (paraneoplastic rashes)
- Auto-immune conditions (Thyroid disease, Diabetes)
- HIV
What is Acanthosis Nigricans
- Associated with insulin resistance, obesity, malignancy
- Flexural distribution
- Hyperkeratosis and Hyperpigmentation, papules
- ‘velvety’ appearance
- Type 2 DM
Name a thyroid skin disease
Pretibial Myxoedema
What investigation is sued of a bacterial infection is suspected
Charcoal swap
Microscopy
Culture
Sensitivity
What investigation is done if a viral infection is suspected
• Viral swab for PCR
What investigation is done if a fungal infection is suspected
- Skin scraping
- Nail clipping
- Hair sample
- Fungal cultures (take several weeks)
