A
man ate fresh pineapple. When he went outside in the sunlight,
all exposed skin developed a red, itchy "rash". Why?
This could be Phytophotodermatitis caused by scratches from pineapple
leaves and fruit.
http://www.lni.wa.gov/Safety/Research/Dermatitis/files/plant_rash.pdf
Acidic juices including pineapple juice are associated with allergic
eczema.
http://www.holistickids.org/pdfs/eczema.pdf
Ananas comosus [pineapple] can cause dermatitis when juice rubbed
into skin
http://www.doacs.state.fl.us/pi/enpp/botany/images/poisonplants.pdf
Pineapple is sometimes implicated in irritant contact dermatitis.
http://www.blackwell-synergy.com/links/doi/10.1111/j.1398-9995.2004.00567.x/abs/
However, this article also mentions "Phototoxic contact dermatitis" where
it says "The occurrence of this type of reaction is increasing
in individuals who apply perfumes and cosmetics that incorporate
bergamot-containing spices." So perhaps the man should
change his/her deodorant!
Bromelain (an enzyme present in pineapple) is often taken as an
herbal medicine to treat swelling, pain, and tenderness caused by
inflammation. It is also used to treat menstrual (period) problems,
decrease blood clotting, and help in the breakdown of food (digestion).
One of its common side-effects when taken in therapeutic doses is
a skin rash. Reference here.
Liz Rylott comments:-
I think the cause may be a thiolprotease.
There is some data on a natural rubber latex allergy that people
have developed in response to exposure to fig fruit and ornamental
house plants in the Ficus genus (Ficus elastica; common name Rubber
Plant!) known as 'Ficus-fruit syndrome'.
A similar response is seen in other tropical fruits, including pineapple.
In pineapple it may be the thiolprotease bromelain (from Bromeliad,
the family name) this has been linked to allergic reactions (asthma
and skin rashes) in about 1% of population.
However, I could find no reference to sunlight.
John Hewitson, Jan Barfoot and Liz Rylott
