Hair loss after Hep B vaccine for my twelve year old?

Last week I noticed there was a big thinning patch on my daughter's head, spreading back from her temple. She has very long thick dark curly hair that she wears with a big side swept fringe which covered it up quite a bit, so who knows how long it had been there. Over the last week, the balding patch has spread right over the crown of her head, following her side part. The skin isn't completely smooth - there are nobbly hair follicles left behind. The hair around the balding patches is breaking off and there are spiky bits everywhere.

I've got an appointment tomorrow afternoon at the doctor, but just curious if anyone else has dealt with this and what it might be. I've asked Dr Google. He tells me it could be stress, a fungal infection, hair pulling (she straightens her hair a lot and puts strain on the hair that part of her head) or, what seems a distinct possibility, a rare reaction to the Hep B vaccine she received about three weeks ago.

The poor kid is freaking out - it's her first year at highschool and she's terrified she's going to lose the lot and be teased mercilessly. If it gets much worse, I don't know whether it would be better to just bite the bullet and have the whole lot cut really short and start again, or try to disguise it with what she's got left but then run the risk of the weight of it putting even more strain on what's left, since it's obviously brittle.

I had a friend suffer from hair loss in high school, and it was not fun for her. The cause was not vaccination, but thyroid issues, but I would not be surprised if this was a rare side effect as the timing does seem suspicious. In my friend's case it grew back in her late teens and was much thicker and lusher than it had ever been before.

Depending on what the doctor says I would be tempted to persuade her to have it cut short and protect the hair that is left from it's own weight. Good luck at the doctors.

Thanks Traveller - I did warn dd that she would probably have to have a blood test to check her thyroid and iron levels. She eats like a horse so I doubt it is dietary. She's also growing extremely quickly at the moment - her feet have gone up three sizes in six months, and she is getting so tall, she's nearly as tall as me already!!

Her hair really is her crowning glory. She was born with a full curly mop of hair and it has just been glorious ever since. If she loses it, it will be just awful for her. She's not vain about much, in fact she considers herself quite plain (the opposite is true!) so having to worry about her hair going will be just devastating.

I really sympathise with your daughter. High school is hard enough without this added trauma. A good hairdresser will be able to disguise her thinning locks though with a funky new style which will possibly even make her feel more secure. It's a hard one though.

I forgot to update this. Turns out dd was (and still is) pulling the hair out herself. She is now nearly bald all over the top of her head. :-( she is seeing a counsellor for anxiety issues and OCD. It's all a bit distressing!