In the old days when people made their own lye from wood ashes, soapmaking was a chancey business. Even more recently, if the lye isn't measured precisely, it is possible to make soap that's "lye-heavy" which will, indeed, irritate the skin. This is the source of the old-wives-tales about lye soap burning the skin. ALL soap is lye soap, there is no other way to make it.
Yes and while we're at it, glycerin is a by product of soap. Lye is still used.
As for the sensitive skin, sometimes some 100% liquid Olive oil soap is the best.
Please those of you who make soap correct or add to this if you'd like! I love soap discussions!
If interested in making hard soap (not liquid): goatmilk, honey, and finely powdered oats in at least a 70% of olive oil is an excellent soap for skin that is sensitive. In fact you could use a combo of 60% Olive, 15% Neem oil (stinks to high heaven but in smaller ratios its not bad), and the rest (25%) a hard oil such as Babassu or Coconut. It won't lather up real well but it wouldn't be harsh on the skin and the neem might be helpful to the inflammation caused by eczema, psoriasis or other issues. It really isn't that hard to make a goatmilk soap. I use pure and no water added. Just watch how much honey you put in. LOL. Honey will cause higher temps and burn the milk. You could also use buttermilk. I have done this because I couldn't get goatmilk.
As for the oil combo, if someone would like to add more suggestions I too would like to hear them!!
Sigh...I really miss making soap. I really miss having soap making buddies.
wanderingherb