lở

Etymology 2
Might be simply a semantic extension/semantic alteration of the etymology above. If this is indeed true, this word has the same origin as and ; these three forms would be from three dialectal areas (giở from inland Northern Vietnam, lở from coastal Northern Vietnam, and trở is the Central-Southern form), but had all entered modern written Vietnamese, albeit with altered semantics.

Verb

 * 1) to break up and fall down; to tumble down; to crumble; to collapse
 * 2) to have a pustular skin eruption, especially one that is painful and itchy