Introduction to Dermatology Flashcards
What adnexal structures are part of the skin?
Hair
Nails
Glands
Sensory structures
What are the layers of the skin?
Epidermis
Dermis
Subcutaneous tissue
What determines skin colour?
Melanin
What are the two types of melanin pigmentation?
Eumelanin
Phemelanin
In darker skin tones, is there more eumelanin or phemelanin?
Eumelanin
What are the three phases of the hair cycle?
Anagen
Catagen
Telogen
Anagen?
Active growing phase
80-90% of hair in this stage
Catagen?
2-3 week phase growth stops and the follicle shrinks
1-3% of hair
Telogen?
Resting phase for 1-4 months
UP to 10% of hair in a normal scalp
Functions of the skin?
Thermoregulation- insulation and heat transfer
Skin immune system
Barrier- protection but also keeps in water and electrolytes
Sensation
Interpersonal communication e.g. physical appearance, smell
What vitamin synthesis does the skin play a role in?
The synthesis of vitamin D
How does the skin have a role in vitamin D synthesis?
UV light converts 7-dehydrocholesterol to cholecalciferol
List some external causes of skin disease.
Temperature
UV light
Chemicals- allergen or irritant
Infection
Trauma
What are some of the internal causes of internal disease?
Systemic disease
Genetics
Drugs
Infection
Autoimmune conditions
What can cause skin photosensitivity?
Medications
->usually only exposed sites affected, often under the chin and behind ears are spared so worth checking is suspecting due to photosensitivty
Which types of light can cause photosensitivity?
UVA, UVB or visible light or a combination of these
List some skin conditions which can be caused for external causes.
Cold injury e.g. frostbite, chilblains
Skin necrosis
Cold urticaria
Which type of photosensitivity does suncream help with?
UVB photosensitivity