Contact dermatitis Dan

Question 1

What are the causes of airborn pattern plant contact dermatitis/ Australian bush dermatitis?
What do they X-react with?
What is the aetiology and relationship to CAD?

Answer 1

Compositae (asteraceae) e.g. parthenium weed (ragweed), cape weed
in ABS – compositae mix, sequiterpene lactone (SL) mix
X-react w/ Balsam of Peru and colophony
It is theorised that a reaction occurs between plant material in this species and human DNA which renders the patient photosensitive accounting for high rates of compositae allergy in pts with CAD

Question 2

What are the causes of streaky pattern acute allergic plant contact dermatitis?
what are the allergenic chemicals?

Answer 2

Toxicodendrons inc poison ivy, poison oak, poison sumac, rhus (toxicodendron Succedaneum)
Grevillea esp Robyn Gordon (proteaceae - resorcinol), mango sap, cashew tree, Brazilian pepper tree (all anacardiaceae – resorcinol)
QLD umbrella tree & English ivy (both araliaceae – falcarinol) – X-react w/ Umbelliferae
These are NOT in ABS - potent allergens, not in ABS to avoid sensitizing.
Toxicodendron and resorcinol types all X-react as they all contain Urushiols (mixtures of catechols and resorcinol

Question 3

What are the causes of fingertip distribution plant ACD?
what are the chemicals involved?
Who is affected?

Answer 3

Alliaceae (Allium) group; Garlic, onion, chive (diallyl disufide) – affects chefs, home cooks
Liliaceae group; bulbs of tulips, peruvian lily (tuliposide A) – affects florists w/ combined ICD (from Calcium oxalate raphides) & ACD (from tuliposide A)
NOT in ABS, but in plant series

Question 4

What plant allergens are more commonly found in medicaments and fragrances than direct plant contact?

Answer 4

Tea tree oil (in ABS – di-limonene) in medicaments – X-react w/ compositae
Feverfew (compositae) in medicaments
Balsam of Peru (Myroxolon pereirae) – X-react with composita

Question 5

c

Answer 5

c

Question 6

What are the causes of phytophotodermatitis?

what is the aetiology?

Answer 6

ARM and Leg - rash seen on extremeties
Apiaceae (Umbelliferae)
-	Parsnip 
-	Celery 
-	carrots
-	Parsley 
-	Cow parsley/hogweed
-	Giant hogweed 
Rutaceae
-	Bergamot lime (Citrus bergamia) also causes berloque dermatitis
-	Citron (Citrus medica) 
-	Pomelo (Citrus maxima) 
-  Ruta spp ('Rue')
Moraceae  
-	Fig 
Leguminosa 
-	Beans  

Phytophoto is a type of phototoxic rcn mainly due to plant furocoumarins, not a photoallergy

Question 7

What cross reacts with PPD allergy?

Answer 7

PABA and its derivatives;

• IPPD
• PABA containing sunscreens
• ester local anessthetics (benzocaine on ABS)
• Parabens (preservative in lignocaine)
• Sulphonamides
• Sulphonylureas
• Thiazides