Beverle Sweitzer wrote:

>    Two years ago I got itchy patches in my hair line at the back of my
>head and on my elbows and the under side of my forearm.  I assumed it
>was some form of food related psoriasis - but mine comes in the summer
>and is gone in the late fall and winter.

Sounds like it could be dermatitis herpetiformis, which is related to
gluten consumption. Note common locations, and triggers of an attack can be
sunlight:

A new unscratched lesion is red, raised, and usually less than 1 cm in
diameter with a tiny blister at the center. However, if scratched, crusting
appears on the surface. The "burning" or "stinging" sensation is different
from a "regular" itch, and can often occur 8-12 hours before a lesion
appears.

The most common areas are the extensor surfaces of the elbows and knees,
back of the neck and scalp,
upper back, and the buttocks. Facial and hair-line lesions are not
uncommon; the inside of the mouth is rarely affected. The rash has
symmetric distribution.

Several physical triggers are known to set off an attack of DH, especially
exposure to iodides and bromides which are contained in household cleaners.
Other triggers of an attack are sunlight and pre-menstrual hormones.
Ibuprofen (NSAIDs) types of pain relievers may increase DH problems.

For images of severe cases see:

  http://www.panix.com/~donwiss/index.shtml#DH

Don.