Bleaches that contain persulfate salts (e.g. ammonium persulfate
or potassium persulfate) may trigger immediate
reactions such as rhinitis, asthma, contact urticaria, and
even anaphylaxis. The underlying immune mechanism, however,
is not known.53
Breakage of disulfide bonds has the following effects on
hair:
- Increased cuticle porosity (porous hair).
- Increased hydrophilia of the shaft (swollen hair shaft).
- Increased brittleness due to porosity and swelling.
All these effects cause cosmetic changes that lead to
styling difficulties and may mimic some intrinsic hair disorders,
such as certain forms of alopecia in which appearance
is consistent with hair shaft breakage near the scalp.
The detrimental effects of hair dyes may be minimized by
using other hair cosmetics (maintenance cosmetics, which
improve styling and protect the cuticle).