If it is fungus, would it be easily contagious to the point that just having her in the house would mean I'd probably get it? Obviously we'd not share the same towel etc but some things would probably be unavoidable, like using the same toilet seat.

Here is what she got tested for at the allergist, it was all negative except for an observation with the hemogram, possibly a bit of anemia I guess. Does the fact she was tested for chicken egg and fish allergies and those were negative mean it can't be urticaria? She used to have some issues with eggs a long time ago but it's been fine the last few years. I've translated as best as I can from Portuguese.
Hemogram Imunoglobine IgA Imonoglobine IgE I...........IgG I..........IgM Rast F2 cow's milk Rast flour Rast F245 chicken egg Rast fish Rast F14 soya Rast F13 peanuts Rast latex Rast MX2 Cd3 CD 4 CD 8 CD 19 Micology Culture Bacterioscopy NK
She had her lip checked for fungus (said she didn't check elsewhere as it was sore). Previously she's had results both saying that she's had fungus that has proliferated everywhere and also negative results! The test on her lip, which was bad, said simply "rare fungal cells in germination and rare hyaline hyphae septated". An older test from back in May said she had malassezia furfur but the doctor then explained everyone has it so it's not a concern. I think that's when the result said that the fungus was proliferated.
She's been on Itraconazole at least twice, one a few weeks ago and once a few months ago. I think she was on it more than that before, too. The most recent time a few weeks ago was for 10 days only. She also has an antifungal cream that she is using, Butenafine, but she says sometimes it's in too many places to cover. In the early stages a few months ago, they did think it could have been allergies so she was on corticosteroids and steroids.
She talks a bit as if these things are almost 'alive' in that they will quickly disappear and be fine but then suddenly reappear and be super itchy. It seems to not be vey consistent in that she'll think she's winning the battle and be feeling much better and then suddenly have a bad outbreak one night.
Her diet, as perscribed by the nutritionist, is pretty much based purely on vegetables, eggs, and meat. All carbs (rice, pasta, etc.) and dairy have been removed, as well as all sugars and yeast-based products. Her diet is pretty much: scrambled eats with vinegar, green tie with coconut oil, ginger. Lots of vegetables like spinach, broccoli, peas. Quinoa. Only grilled meat and fish, no oils. Eggs twice a day.
My mom says that they are in circles or straight lines, and she can see where the fungus is. She says it is always itchy and there are bigger and smaller spots. I've not managed to get her to figure out how to take a photo yet and send it to me, but I am working on it.
Thanks!

Yeah, at first they thought it could be allergies and thus the medicines she got for that, but it seems like they think it is fungal now, but just can't seem to manage to treat it!
I think there was a bit of miscommunication as to how exactly it looks so I've asked exactly: she says it looks more like pytiriasis persicolor, with yellow-ish/pale skin in circles or lines (though she said there's some red bumps on her leg). They can be anywhere, though she has plenty on her face, lips, mouth, etc. She says they are flat. She says they don't disappear but rather spread. She says they itch/feel like bites, even though they don't necessarily look like them.
Still trying to get those photos, soon hopefully! She's trying to figure out how to do it.

I got photos now. The first shock was just how old my mother looks compared to when I last saw her only a year ago - she honestly has aged 10 years old patientin 1 year, and she has lost a ridiculous amount of weight! Probably because of that super strict diet she is on. You can zoom in to see if you can actually see anything on the skin(looks like pityriasis).
With regards to lichen sclerosus - it seems to be mostly around the vagina and anus, not so much the face and places like that?
Some other new points:
She went to the dermatologist on Friday again. The dermatologist looked at all her recent tests and said she was all fine. She also said she has no fungus on the skin (keep in mind, however, that previous tests a while ago showed a proliferation of fungus). The micrological tests were fine and she did not want to prescribe any medicine. This week she is going to do another micrological test on the tongue and around the mouth. She also recommended getting an endoscopy in the esophagus and a biopsy -- not sure why though, in case there is fungus inside? She also recommended going to a doctor about 3 hours away to an autoimune clinic to do tests.
The allergist, however, does think it is pityriasis versicolor and wants to prescribe her Itraconazole for a month and the cream.

Regardless of what it is, I have bought dermol 200 which is a shower emollient to have something easier on the skin - this is a good product regarldess of the condition, right?

Thanks again for the help.