Non-scarring patchy alopecia in patients with systemic lupus erythematosus differs from that of alopecia areata.

BACKGROUND: Non-scaring patchy alopecia associated with systematic lupus erythematosus (SLE) is sometimes mis-diagnosed as alopecia areata (AA).

OBJECTIVES: Our aim was to differentiate non-scarring patchy SLE alopecia features from patchy AA.

METHODS: Clinical, dermatoscopic and histopathological data from 21 SLE patients with patchy alopecia were compared with data from 21 patients with patchy AA.

RESULTS: Incomplete alopecia was common in SLE alopecia patches, while AA patches exhibited complete alopecia. Exclamation-mark hairs, black dots, broken hair and yellow dots were common to AA, while hair shaft thinning and hypopigmentation, angiotelectasis, peripilar sign, perifollicular red dots, white dots and honeycomb pigment patterns were more common in SLE. Interfollicular polymorphous vessels were the most common angiotelectasis presentation in the SLE alopecia patches, but interfollicular arborizing vessels were significantly more common in non-hair-loss-affected SLE regions and in AA hair-loss regions. During follow-up, increased vellus hair was the earliest feature that emerged after treatment both in SLE and AA, while the earliest feature that disappeared was hair shaft hypopigmentation in SLE and broken hair in AA. After treatment, no SLE patients had relapse of alopecia, while 41.7% of AA patients did.

CONCLUSION: Distinct clinical, dermatoscopic and histopathological features were found in SLE-associated alopecia regions, which were different from those of AA. Serological autoantibody tests are of value to confirm the differential diagnosis. Local angiotelectasis and vasculitis close to hair follicles may be involved in the pathogenesis of alopecia in SLE.