Granuloma annulare (GA) and necrobiosis lipoidica (NL) are granulomatous diseases of undetermined etiology. Rarely, both dermatoses have been reported to occur concomitantly in patients. GA and NL are characterized histologically by areas of necrobiosis of collagen. The two diseases share some common characteristics, which may suggest that these dermatoses could occur as a spectrum in some patients or possibly share a similar pathogenesis. We report on a 67-year-old Caucasian woman with a history of NL on the anterior shins that later developed lesions of GA on the breasts, trunk, and wrist. We also review the literature and discuss the characteristics of patients with concomitant GA and NL.

Background: Psoriasis and vitiligo are 2 autoimmune conditions that can occur concurrently in patients. At present, no single systemic therapy has been identified to be effective in treating both the conditions. Observations: Recent advances in our understanding of the T helper (Th) 17 subset of Th cells suggests that interleukin (IL)-17 may play a key role in the pathogenesis of both vitiligo and psoriasis. We report a case of anatomically superimposed psoriatic plaques and vitiligo for which treatment with ixekizumab leads to resolution of psoriasis but did not improve the patient's vitiligo. Conclusion: While IL-17 is highly effective in the treatment of psoriasis, it does not seem to be an effective treatment for vitiligo.

ridges and less within the furrows of the dermatoglyphs. Subsequent histopathologic analysis of those lesions demonstrated atypical melanocytes containing melanin granules within the crista profunda intermedia. 6 Similarly, in their retrospective analysis of Japanese patients with melanocytic lesions, Saida et al 5 found the parallel ridge pattern more diagnostically accurate of melanoma in situ than "irregular diffuse pigmentation." 5(p1235) Melanocytic nevi, subcorneal hemorrhage, exogenous pigmentation, and lentiginosis and drug-induced hyperpigmentation can demonstrate a dermoscopic parallel ridge pattern. 3 Benign dermoscopic attributes include a parallel furrow pattern, 5 a lattice-like pattern, 6 and/or the lack of disruption of the acrosyringia within the epidermal ridges. 3 Our patient's history suggested recent onset, an uncommon feature in ALM. Because we did not specifically inquire about exogenous pigment exposures, our initial evaluation failed to reveal information that may have allowed for earlier exclusion of ALM. Our case serves as a reminder to clinicians of the importance of a thorough history. Exogenous tissue dyeing should be considered in the differential diagnosis of acral pigmented lesions, particularly if the clinical history suggests the lesion is of recent onset.