Permanent wave solutions break the bonds that hold hair together and then reform them. But with a perm that is not diluted right or not rinsed off properly, for instance, those bonds may not re-form and the hair would soon fall out as a result. Fortunately, most professional hair dressers know how to use perms correctly, says Storrs. Most hair dyes are not as irritating as permanent solutions, mostly because they do not break the bonds between hair fibers and are therefore not likely to cause a hair loss, she says. However, a severe allergic reaction to hair dye could cause hair loss.
Permanent solutions can also cause allergic reactions, though that's a rare side effect.
If the hair breaks often enough, the follicles may eventually not be able to produce normal hair, says Bihova. Rough shampooing may accelerate any loss, though it's usually not a problem in people with healthy hair. Alopecia areata often causes small, oval or circular areas of hair loss. Although the loss is usually temporary, the condition can recur. Treatments include topical steroids or the use of chemicals to produce an allergic reaction to start the hair growing again.