between prepubertal nonsegmenal vitiligo (NSV) and AD, and a possible shared mechanism for both. 1 However, the association of AD and SV has not been clearly established.To our knowledge, this is the first case report of spreading of SV after immunotherapy in a patient with AD. Such spreading is not thought to be associated with an autoimmune process, although SV has recently been reported to share an autoimmune mechanism with NSV. 2,3 Although SV is usually explained by the neural hypothesis, this case supports a recent hypothesis that SV has a similar immunological mechanism to NSV in its development. 3 A CD8+ melanocyte-specific T cellmediated immune response is known to play a role in SV with associated halo naevi, similar to NSV. 4 It has been reported that dysfunction of humoral immunity may play a role in the progression of SV, whereas cellular immunity seems to be involved in NSV. 5 T helper (Th)1/Th17 cellular immunity is thought to be involved in the pathogenesis of vitiligo, whereas AD is regarded as a Th2-skewed allergic skin disease. The mechanism of immunotherapy in AD is to downregulate Th2 response and to upregulate the Th1 pathway through allergen sensitization. Thus, our case shows that immunotherapy in AD could aggravate vitiligo via an immunotherapy-induced Th1 immune response.The presence of AD lesions over the dorsum of the patient's left foot might indicate development of vitiligo lesions through koebnerization. However, this does not explain the spreading of vitiligo lesions on the left abdomen, which was not accompanied by AD. Furthermore, the AD lesions were bilateral and the vitiligo lesions were unilateral.In conclusion, our case suggests that immunotherapy for AD treatment could initiate spreading of SV, and that SV might have an overlapping immunological mechanism with NSV.