3.C Photosensitivity -Chemically-induced

Question 1

Types of Photosensitivity disorders

Answer 1

Chemically-induced
Metabolic
Idiopathic
Light-exacerbated

Question 2

Substances that induce an abnormal reaction in sun-exposed skin or equivalent light emitting source.

Answer 2

Photosensitizers

Question 3

Difference between Phototoxicity and Photoallergy:

Answer 3

Phototoxicity:

• Anyone with exposure to photosensitizer and sunlight
• Sunburn-like
• Within the affected area only
• Onset : < 48h

Photoallergy:
- In sensitized persons only
-Contact dermatitis-like
- Delayed Onset: up to 14 days
-

Question 4

Molecular weight of photosensitizers

Answer 4

Less than 500 Daltons

Question 5

Specific wavelengths of light that evoke reaction

Answer 5

Action spectrum

Question 6

Action spectrum of Photoxicity

Answer 6

320nm-425nm

Question 7

What conditions precede photosensitivity

Answer 7

Sufficient

• Concentration of photosensitizer
• Intensity of light
• Duration of light

Question 8

Onset of erythema in Phototoxicity

Answer 8

2-6 hours

worsens for 48-96 hours

Question 9

Exposure of nail bed in phototoxicity results to

Answer 9

Photo-onycholysis

Question 10

Phototoxicity due to Coal tar, creosate, crude coal tar or pitch

Answer 10

Phototoxic Tar Dermatitis

Question 11

Skin type protected for hyperpigmentation in Phototoxic Tar Dermatitis

Answer 11

Types V and VI

Question 12

Where is coal tar found?

Answer 12

Cosmetics
Drugs
Dyes
Insecticide
Disinfectant

Question 13

Phototoxic reaction caused by Furocoumarins in plants.

Answer 13

Phytophotodermatitis

Question 14

Inducers of Phytophotodermatitis

Answer 14

Fragrance with Bergapten

Berloque Dermatitis

Question 15

Characteristics of Berloque Dermatitis.

Answer 15

Hyperpigmentation preceded by redness and edema on the Neck and Face.

Question 16

Families of most phototoxic plants:

Answer 16

Umbelliferae
Rutaceae
Compositae
Moraceae

Question 17

A phytophotodermatitis caused by contact with yellow-flowered meadow parsnip or a wild yellow-flowered herb of the rose family.

Answer 17

Dermatitis Bullosa Striata Pratensis

Question 18

Characteristics of Dermatitis Bullosa Striata Pratensis

Answer 18

Streaks and bizarre configurations with vesicle and bullae.

Heals with residual hyperpigmentation

Question 19

Common fruit that causes phytophotodermatitis

Answer 19

Lime

Question 20

Difference of Blistering phytodermatitis to Rhus Dermatitis (Urushiol)

Answer 20

Blistering Phytodermatitis

• Sun-exposed sites
• Burning pain within 48h
• Marked hyperpigmentation results

Rhus Dermatitis

• Not limited to sun-exposed areas
• ITCHING prominent
• Duration: A week or more

Question 21

Treatment of Phytodermatitis

Answer 21

1. Cool compress
2. Mild analgesics
3. Topical emollients

Question 22

Treatment of hyperpigmentation in Phytodermatitis

Answer 22

Tincure of time

Topical steroids and strict sun avoidance may protect againt hyperpigmentation