Conflict of interest: none declared. A 20‐year‐old man presented with recent development of alopecia areata (AA). There were no associated autoimmune diseases or family history. The patient had Down syndrome (DS) and long‐standing early‐onset chronic plaque psoriasis. On physical examination, extensive inflammatory psoriasis was seen on the scalp, sparing the areas of AA. Localized patches of nonscarring hair loss were found on the apex and occipital scalp, the largest measuring up to 20 mm. Using dermatoscopy, evidence was found of perifollicular pigmentation, early peripheral poliosis and exclamation hairs, in keeping with the diagnosis of AA. Large confluent plaques of psoriasis encroached on the areas of AA, but abruptly stopped and did not pass within these areas (Fig. 1). This was unique to the scalp, with no similar features seen at other body sites. DS is known to be a risk factor for the development of autoimmune conditions including AA. The coexistence of AA and psoriasis has been reported previously, but to our knowledge, the development of alopecia specifically spared by psoriasis has not been reported. One case of an analogous situation has been reported as a so‐called ‘Renbok phenomenon’, in which hair growth occurred only within psoriatic plaques in a patient with extensive AA.1 This is in contrast to the more common Koebner phenomenon, where there is provocation of psoriasis at sites of alopecia.2
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