Flashcards in Photodermatology 1 - Introduction to photo dermatology and porphyrias Deck (30):
What is photo dermatology?
The study of the effects of light on the skin
What are porphyrias?
A group of rare, hereditary diseases in which there is abnormal metabolism of haemoglobin - causes symptoms such as dark urine, mental disturbance, light sensitivity
What is photobiology?
The study of non-ionising radiation on living systems
What 3 types of UV rays does sunlight produce?
What has a longer wavelength: UVA or UVC?
Does visible light have a longer or shorter wavelength than UV radiation?
Does UVA or UVB penetrate deeper into the skin?
UVA - although UVB has more energy and therefore does more damage to the skin
What type of UV radiation doesn't tend to reach the Earth?
What scale classifies skin types depending on their reaction to the sun?
Fitzpatrick Sun-Reactive Skin Phototypes
What skin type burns very easily and never tans?
What skin type burns easily and rarely tans?
What skin type rarely burns and tans easily and quickly darkens?
What skin type sometimes burns and gradually tans?
What skin type hardly ever burns and tans very easily?
What skin type never burns and tans very dark?
Describe the appearance of someone with skin type 4?
Brown hair, hazel/ brown eyes, light brown skin
Describe the appearance of someone with skin type 2?
Blonde/ red/ light brown hair, blue/ green/ hazel eyes, pale white skin
Describe the appearance of someone with skin type 5?
Dark brown hair, brown eyes, brown skin
Describe the appearance of someone with skin type 6?
Black hair, brown eyes, dark brown/ black skin
Describe the appearance of someone with skin type 3?
Chesnut/ dark blonde hair, brown/ green/ blue eyes, darker brown skin
Describe the appearance of someone with skin type 1?
Red/ blonde hair, blue eyes, very pale/ pale white skin
What are treatment options for photodermatoses?
Inhibition of mediator release
Inhibition of inflammatory response
What is the purpose of phototherapy?
UVA and UVB have a suppressive effect on skin inflammation and there is increasing evidence that they can suppress systemic immunoreactivity
Is UVA or UVB more carcinogenic?
What are the 2 main types of phototherapy and what is used preferentially?
Narrow band UVB - used preferrentially
What is PUVA?
Combination of UVA with psoralen, a light sensitiser, as UVA is relatively ineffective on its own
What are the risks of phototherapy?
How are these risks reduced?
Can cause skin ageing and skin malignancy if used in excess
Unaffected/ high risk areas can be screened
How is narrow-band UVB used in treatment of eczema and psoriasis?
Given 3 times a week for 6-10 weeks
How often is PUVA given?