I’m not a Physician, or a dermatologist, nor do I have any kind of medical training.
I do, however, formulate a mean body lotion, and I’ve done things in a lab that will make your hair curl (Perm anyone)
Working where I do, we do get customer enquiries and complaints. We do try to formulate stuff that most people can use, but there is always one person out there who is going to react to what you make. I guarentee it.
Anybody who claims to make products that no-one reacts to is a …Pedlar of false dreams
My advice if you have sensitive skin, know what it likes. Take time to understand what helps YOU.
The most common causes of skin allergy are:
1) Metal Allergies. Good ol’ Nickel. Get rid of the cheap market stall Bling. It looks shit, brings you up in hives, and green stains are so last year dahling.
2) Fragrance, you may find that some of the perfumes in your fave brands will cause a reaction. It sometimes happens
If your beauty products can knock flies off manure, try the Fragrance free version. Most of the big boys have cottoned onto this, so they sell the fragrance free version of the flagship product. Either that or go for a Brand that makes a point of being fragrance free.
If you’re finding that you are a really sensitive skin, if you try a new product, try a little bit first. Don’t slap half a bottle on if you’re uncertain. Please. You don’t need the experience and I don’t need to see the photographs of that.
3) Now we descend into the area of really sensitive skin. Preservatives can cause allergies. I’ll admit it. I put preservatives into products to be put on the skin. I’m A bad person.
Err no, I’d rather have a product that causes a minor irritation due to a sensitivity to a preservative, rather than someone putting a bacterial soup onto their skin and getting blood poisoning.
The ones that tend to cause problems are
Methylchloroisothiazolinone, Methylisothiazolinone (Common in most wash off products, that are in brief contact, like shower gel, shampoo, handwash etc)
Formaldehyde donors such as DMDM Hydantoin, or Imidazolidinyl urea, or diazolidinyl urea
Methyldibromo Glutaronitrile (Now restricted by the EU primarily to wash off products)
IF IN DOUBT READ THE LABEL! There is an ingredient listing on every pack., or if its really small it has to be attached to the pack or positioned at the point of sale. As a formulator it takes a lot of hard work to pull those together. They have to be checked and double checked to make sure they’re right.
And before I finish, I’ll repeat an oft quoted warning
If in doubt, discontinue use and if irritation persists consult a Physician or Pharmacist. They studied long and hard to get qualified. You may as well use them
We sell dreams in a bottle 
Emulsifying liquid and Aqueous Solution can be your friends if you have very sensitive skin. Dilute with water to preference-small amounts-if you mix too much, keep it in the fridge – you definitely need to do this when you are mixing products without preservatives.
Absolutely, couldn’t agree more that any new product has to be patch-tested on your skin, even so-called hypoallergenic, safe-for-baby stuff. Despite these precautions, you will be caught out from time to time because manufacturers tweak products without publicising it.
Pharmacists are a fund of information as to the correct anti-histamine pill or soothing cream should you need that advice, as you say.
Saw glass poetry on Flickr and it made me think of your blog title – it is Creative Commons as well.
Wrong one – this is the glass poetry link.
Kewl!
Must look at that later.
The “Dreams in a bottle” is a quote I heard around the industry years ago, as is the phrase “Value added water”.
I’ll have to do a list of other euphemisms that we use sometime, but some of them are a little rude.