Paraphenylenedeamine (PPDA) is an ingredient found in permanent hair dyes. This ingredient is mixed with an oxidizing agent, such as peroxide, before application. People allergic to PPDA should not use any permanent hair dyes. About one fourth of the people allergic to PPDA are also allergic to ingredients in semi-permanent dyes. Follow the package instructions for a patch test before using any hair dye. Most PPDA allergic people can use temporary dyes or rinses, to blend in gray and brighten hair. A few people, however, will react to these dyes also.
Butternut squash and Acorn squash have been known to cause an allergic reaction in many individuals, especially in food preparation where the squash skin is cut and exposed to the epidermis.  Food handlers and kitchen workers often take precautions to wear rubber or latex gloves when peeling butternut and acorn squash to avoid temporary Butternut squash (Cucurbita moschata) dermatitis  A contact dermatitis reaction to butternut or acorn squash may result in orange and cracked skin, a sensation of "tightness", "roughness" or "rawness".