This, it was likely temporary but it's also possible she had a biotin deficiency since there's only copious amounts of the compound in food. Nuts, eggs, yams, fish, spinach, carrots, cauliflower, avocado, etc. If you eat all this stuff daily you're only going to get around 100-500 mcg of biotin (but at a much better absorption rate). The highest packing supplements are 5,000mcg to 10,000mcg.
10,000 mcg (10mg) gives me a headache so I cut them in half and take 5,000 mcg. Didn't notice much for hair on the head other than faster regrowth rate, but my eyebrows 100% thickened and so did my eyelashes. A lot of women take this supplement for that reason, so it's still a nice bonus and certainly can't hurt.
@AnxiousAndy
Since you're already trying all sorts of stuff, try making your own topical cetirizine, if you're interested let me know and I'll lay it out on how to make it pretty cheap and easy.