Sounds like an allergy to me. Around here, Deva is a love/hate line. Many of us started out with Deva, think we like it. Then move on to things we like MUCH better.

The best way to choose ingredients/products is by hair properties. Here's a link to help you with yours Live Curly Live Free - Curly Hair Basics Once you determine your properties, look for folks with hair like yours and see what they use (in signatures.) It's the best place to start.
3a (Corkicelli), highlighted, fine, low porosity
modified CG, since April '07
CG since 3/11/08

SE PA

HGs: Anything Sevi; Curly Kinks Satin Roots, Curlycue ReNew and Coil Jam; homemade FSG and okra gel; soap bars; UFD Curly Magic (now Hello Curly Curl Stimulater); Botanical Spirits Jellies, CJ Repair Me, Aloe Fix and CCCC