The question has been asked but not, as yet, answered. Two dogs in the same household are similarly affected, but is the pattern the same - are the lumps in the same place on both dogs ?
Years ago, one of my Basenjis lost his fur down both sides, completely symmetrically. The skin became dark and leathery. We tried everything, vets, herbalists, homeopathic practioners. The main consensus was that, because it was symmetrical and equal on the two sides, it had to be glandular.
It didn't bother the dog in the slightest - it just looked unsightly but even that didn't deter judges from placing him highly, even with raised eyebrows !
Till one day at a show, a fellow exhibitor exclaimed 'you're burning him, Sal.'
Yup - the symmetry was because he would lie facing north, or south, tight against the Aga (four oven kitchen range, coal fired, permanently hot). And we all know Basenji like to lie close to heat.
Marvin deconstructed a wire cage and with that and long pieces of timber, fashioned a fender the length of the Aga, so no dog could lie and actually touch it. About 4 inches separated them from the hot metal.
Within 3 - 4 weeks, with the help of applications of Tea-Tree Oil, Econeem and Vitamin E oil, the fur grew back, completely normally !
So it is always as well to look at the environment when two dogs are suffering similarly. It might just be from external causes.