Photodermatology 1 - Introduction to photo dermatology and porphyrias

Question 1

What is photo dermatology?

Answer 1

The study of the effects of light on the skin

Question 2

What are porphyrias?

Answer 2

A group of rare, hereditary diseases in which there is abnormal metabolism of haemoglobin - causes symptoms such as dark urine, mental disturbance, light sensitivity

Question 3

What is photobiology?

Answer 3

The study of non-ionising radiation on living systems

Question 4

What 3 types of UV rays does sunlight produce?

Answer 4

UVA
UVB
UVC

Question 5

What has a longer wavelength: UVA or UVC?

Answer 5

UVA

Question 6

Does visible light have a longer or shorter wavelength than UV radiation?

Answer 6

Longer

Question 7

Does UVA or UVB penetrate deeper into the skin?

Answer 7

UVA - although UVB has more energy and therefore does more damage to the skin

Question 8

What type of UV radiation doesn’t tend to reach the Earth?

Answer 8

UVC

Question 9

What scale classifies skin types depending on their reaction to the sun?

Answer 9

Fitzpatrick Sun-Reactive Skin Phototypes

Question 10

What skin type burns very easily and never tans?

Answer 10

1

Question 11

What skin type burns easily and rarely tans?

Answer 11

2

Question 12

What skin type rarely burns and tans easily and quickly darkens?

Answer 12

5

Question 13

What skin type sometimes burns and gradually tans?

Answer 13

3

Question 14

What skin type hardly ever burns and tans very easily?

Answer 14

4

Question 15

What skin type never burns and tans very dark?

Answer 15

6

Question 16

Describe the appearance of someone with skin type 4?

Answer 16

Brown hair, hazel/ brown eyes, light brown skin

Question 17

Describe the appearance of someone with skin type 2?

Answer 17

Blonde/ red/ light brown hair, blue/ green/ hazel eyes, pale white skin

Question 18

Describe the appearance of someone with skin type 5?

Answer 18

Dark brown hair, brown eyes, brown skin

Question 19

Describe the appearance of someone with skin type 6?

Answer 19

Black hair, brown eyes, dark brown/ black skin

Question 20

Describe the appearance of someone with skin type 3?

Answer 20

Chesnut/ dark blonde hair, brown/ green/ blue eyes, darker brown skin

Question 21

Describe the appearance of someone with skin type 1?

Answer 21

Red/ blonde hair, blue eyes, very pale/ pale white skin

Question 22

What are treatment options for photodermatoses?

Answer 22

Behavioural Avoidance
Clothing
Sunscreen use
Hardening
Chromophore removal
Inhibition of mediator release
Inhibition of inflammatory response

Question 23

What is the purpose of phototherapy?

Answer 23

UVA and UVB have a suppressive effect on skin inflammation and there is increasing evidence that they can suppress systemic immunoreactivity

Question 24

Is UVA or UVB more carcinogenic?

Answer 24

UVA

Question 25

What are the 2 main types of phototherapy and what is used preferentially?

Answer 25

Narrow band UVB - used preferrentially

PUVA

Question 26

What is PUVA?

Answer 26

Combination of UVA with psoralen, a light sensitiser, as UVA is relatively ineffective on its own

Question 27

What are the risks of phototherapy?

How are these risks reduced?

Answer 27

Can cause skin ageing and skin malignancy if used in excess

Unaffected/ high risk areas can be screened

Question 28

How is narrow-band UVB used in treatment of eczema and psoriasis?

Answer 28

Given 3 times a week for 6-10 weeks

Question 29

How often is PUVA given?

Answer 29

Twice weekly

Question 30

What precaution must be taken when undergoing PUVA?

Answer 30

Eye protection must be worn whole day of treatment as psoralen sensitises the retina (to prevent cataracts)