Pigmentation of the skin after electroacupuncture (EA) or acupuncture in patients is not well recognised. Reporting and studying skin changes after acupuncture or EA would increase awareness among health services providers. This case series includes four cases of short-lived or long-term skin pigmentation after EA or acupuncture. Skin pigmentation or dark spots appeared in these four cases: after 12 treatments in Case 4, during the 14 treatments in Case 3, after one treatment course (16 treatments) in Case 1 and during the sixth month in a long-term treatment of duration 2 years (one or two treatments per week) in Case 2. These skin changes faded gradually after cessation of a course of acupuncture or EA. Skin pigmentation was hardly seen in one case after 14 days, and in another case after 42 days. Pigmentation of the skin could still be seen in one case after 42 days and could still be seen in another case after 2 years, however, in both cases, pigmentation has reduced in size and colour intensity by more than 50%. It is likely that pigmentation of the skin is a specific consequence of needling and may be closely linked to acupuncture dosage regardless of whether stimulation is given manually or by EA.