Increased hair growth
There have been numerous reports of hair growth increasing while using helminthic therapy, along with improvements to fingernails and skin condition.
Decreased hair growth
There have been a few accounts of hair being shed, but, in all but three cases, this has been limited to the side effect phase of the therapy, i.e., the first 2-3 months.
Transient hair loss
Persistent hair loss
The first of the three patients - all female and NA hosts - who have reported hair loss beyond the first few months of therapy has aplastic anemia. It was only after having had NA for two years that she began to lose hair, and she says that it has always grown back whenever she has lost her worms. There were apparently no changes around the time that the hair loss started, either in NA dosing or other treatments, etc., that might account for this effect, so the patient assumed that it must be worm-related. 
The second of these three individuals has reported steady hair loss since first introducing hookworms to treat ulcerative colitis. She had never suffered any hair loss previously, and, once started, it continued until she eventually had barely any hair left on her head. She does say, however, that she will take hair loss over colitis and blood loss any day. 
The experience of the third self-treater is contrary to that of the last individual, in that hookworms proved to be the only species not to cause hair loss.
Change in hair colour
In one case, hookworms proved to be effective for someone who has alopecia as a result of the lupus component of her disease.
- … without a doubt, my treatment with hookworms has been very effective on my bald spots and thinning areas. 
However, most of those who have had success in treating alopecia have used HDC rather than NA.
- I have alopecia and have tried helminths on and off for years, both hookworm and hdc. Hookworm actually made it worse and tons of hair fell out. Had good results initially with hdc. I thought they were a miracle at first, but the good effects wore off about 5 months in, when they stopped working and the hair fell out again. I tried the hdc for quite a while, trying to regain the initial results, but I never got the same hair growth again. If I were to try it again for alopecia I would use hdc. I had the best initial response to alopecia with them. (Edited from several posts.   )
Taking HDC lead to a very quick remission in a case of alopecia areata that had been progressing for 5 years and caused total baldness for 3 years.
- After starting HDC I regained 80% of all hair within about 4 months. 
After subsequently adding NA and maintaining his colony for four years, this same individual has reported that, in the longterm, NA caused neither progression nor regression of his alopecia, but that NA helps him better with other problems. And he added:
- I know another person with AA where HW actually triggered AA, especially in the inflammatory phase. So at this moment I would advise people with AA to give TSO or HDC a try. (Link expired.)
The following three comments were made by a blogger at 4, 5 and 6 months after starting to take HDC every two weeks.
- For over 12 years, I have had alopecia (on my lower legs) and (now) I have hundreds of tiny, fine hairs regrowing, where once there were none. 
- During November, I ran the dust mop after a long lay off … (and) there wasn’t nearly as much of my hair getting picked up as normal. A family member confirmed this observation… I am not shedding as much hair as I normally do, either from my head, or body. Normally, I shed so much hair it is annoying. While that has not stopped completely, it is noticeably less. This would correlate well with the reversal of alopecia on my lower legs I mentioned last month. 
- … all previously described positive benefits were maintained (this month), and to these I would add that the hair on my head is less grey. My sideburns had gone completely grey before worming up. Now they have freckles of dark hair, and my hair is less grey overall, as well. 
Another HDC user has reported:
- I take both HDC (30 every two weeks) and NA to treat asthma and eczema. I also have alopecia universalis, which had been mild most of my life but, when I turned 51, I lost every hair on my body. It had started to grow back before I began taking HDC but, once I started the HDC, it grew very fast until I had a full head of hair. But it can still come and go from pure bald to full hair. (Edited from three posts:   .)
- In a further update, this individual said that, overall, worms have not helped her alopecia. 
The chances of success using helminths to treat alopecia are greatly increased if the therapy is started early, and especially in children.  The more established the condition is, the lower the chance of success.
Alopecia and the gut
- Mechanisms of tolerance and potential therapeutic interventions in Alopecia Areata -- Full text (See section 4: Gut microbiota and helminths, autoimmunity and tolerance.)
- We have seen a link between AA and a dysfunctional gastrointestinal system which raised the hypothesis that an underlying intestinal inflammation drives the priming and dysregulation of immune cells that lead to hair follicle destruction.
In view of this last finding, it might be advantageous to combine helminthic therapy with FMT to address alopecia.