[Differential diagnostics of hypomelanoses]

Hypomelanoses of the skin encompass a wide spectrum of congenital and acquired alterations in melanin pigmentation. These diseases can be localized or universal. The pathobiology of cutaneous hypomelanoses is heterogeneous and includes defects in melanoblast migration from the neural crest to the epidermis, alterations in melanogenesis and melanin transfer to keratinocytes, and destruction of pigment cells by autoimmune and inflammatory processes. Importantly, some congenital forms of universal hypomelanoses are associated with involvement of internal organs (e.g., Hermansky-Pudlack or Chédiak-Higashi syndrome) and require interdisciplinary patient management. In recent years, significant progress has been made in our current understanding of the pathophysiology especially of vitiligo, thus, resulting in promising new treatment strategies. This disease being one of the most common forms of acquired hypomelanoses of the skin can now be treated in a guideline-oriented and evidence-based manner.