The noun dearth, meaning a scarce supply, is synonymous with shortage and scarcity. It does not mean a complete lack or absence. For example, if you have $12.43 in your bank account, you have a dearth of funds. If you have $0.00 in your account, you don’t have enough for a dearth. So phrases like complete dearth or total dearth make as much sense as total shortage or complete scarcity.
Examples
These writers use dearth well:
A seemingly infinite number of op-ed pieces bemoan the dearth of medals we’re earning or have earned . . . [Eccentric Muse]
Aleksandar Hemon points to this dearth of translated literature in his introduction to Best European Fiction 2010, a new anthology. [NHPR]
And these uses of dearth are questionable:
Rare books cataloging systems and the utter dearth of work on pre-nineteenth century paintings makes locating earlier work a difficult task. [Appositions]
That is, Trekkies who are willing to overlook brain-lockingly repetitive gameplay, unvaried design, thin storytelling, buggy client software and an almost complete dearth of meaningful social interaction . . . [NY Times]