The average humidity levels in Australia where vitticeps come from is around 45%

As you can see here, even in an arid area like Alice Springs, sitting right in the middle of Australia, the low is almost 30% and the high is 55%. There are not a lot of dragons there, they are more to the south around the Coober Pedy, close by where the red dragons occur in the wild and that humidity is 30% low in peak afternoon to 50% in the morning and much higher at night. As you move in closer to the Lake Eyre area that has an abundance of vitticeps it becomes low of 45% and high of 70%.

Perfect conditions for reptiles as it is extremely rare for any mold/fungus to develop under 70% humidity, yet they still get the needed optimum RH zone for the well-being of its occupants which is between 30 and 55 % relative humidity.

If you look over all the humidity chart of Australia, you can see how rarely humidity exceeds 70% and where it does the changing lows control the mold/fungus. This is probably why so many species of reptiles have thrived there for so long. You have to soak down a tank pretty badly to reach 70% humidity for fungal problems to develop.

Bearded dragons do get most of the moisture they need from their foods, for cells, organs and overall health, but areas that are air exposed directly such as skin, scales and membranes like the ear and nose will suffer with problems when humidity is under 40% for prolonged period of time. At 40-55% you do not have fungus living or growing, under that you do have dried membranes and shed problems that create skin tags which are breeding grounds for fungi. Contrary to what some advice, you are creating the problems your trying to avoid by depriving them of water and humidity.

The area that vitticeps come from is not arid or desert, this is a huge myth that keeps getting repeated form one person parroting another that does not really know, it is mostly grasslands, along rain corridors and peppered with many small lakes and several very large ones.

Here is a map of Australia you can see the cities, vitticeps come from the area that start at the southern shores near Adelaide, circling around Cooper Creek and Lake Eyre, up to the Alice Springs and Tennent Creek area and back down to the Nullarbor Plains area. It includes most of South Australia, Northeast area of New South Wales, lower Southwest Queensland, and about 1/3 of the Northern Territory. You can also see this area has many lakes and rivers, the most found in Australia.

http://www.worldtravelguide.net/data/aus/ausmap.asp