In dermatology, there are two camps: Lumpers and Splitters. Lumpers tend to collect all of the clinical entities which have similar presentations and or pathology, whereas the splitters are more likely to divide each group into subgroups, then into sub-subgroups. Chronic pigmented purpuras fall into this dilemma, because of the different clinical presentations, but in my mind, I guess I'm a lumper. I just think of all of them as CPPs, rather than adding the eponyms. I think that after I spent time in France, I learned that many of the eponymous diseases were actually closely related to or identical to other very differently named diseases, and so while there I converted to Lumperism, and thus became an apostate to those back in Texas who worshipped the false idols of Splitterism.
That being said, this is a discussion more for splitters than lumpers.
Schamberg's Disease is a condition that fits into the spectrum of diseases we lumpers call capillaritis, which can fit into a variety of clinical syndromes. Ranging from Schamberg's to Lichen Aureus to Majocchi's Purpura to Exercise-induced capillaritis (a variant of Schamberg's), these are really all one disease, albeit with clinically distinct presentations. The underlying disease is an inflammation of the capillaries which then leak red blood cells, which stain the skin. In the more discrete versions of this, the skin is compared to cayenne pepper.
This leakage of hemoglobin into the skin is actually a tattoo, and takes a long time to disappear.
Schamberg's and Exercise induced capillaritis are reflected by small, discrete macules of red-brown pigment, and often come in showers.
Majocchi's is annular, spreads centrifugally, and may itch.
Lichenoid purupura of Gougerot and Blum is more eczematous and pigmented.
Lichen aureus has a bruised, almost golden look and is usually on the thighs or over a varix.
The common thread is the leaky capillaries, and so all are (Hail Lumpers!) capillary inflammation with leakage. So there. I think I've solved the schism between Lumpers and Splitters. For now.
p.s. If you gave me any answer that somehow fit under the broad tent of Chronic Pigmented Purpuras, I gave you credit.