Primary Localized Cutaneous Amyloidosis: A Retrospective Study of an Uncommon Skin Disease in the Largest Tertiary Care Center in Switzerland.

ABSTRACT

BACKGROUND: Primary localized cutaneous amyloidosis (PLCA) is defined by the deposition of amyloid protein in the skin without systemic involvement. There are four subtypes of PLCA lichen amyloidosis (LA), macular amyloidosis (MA), biphasic amyloidosis (BA), and nodular amyloidosis (NA). PLCA occurs most frequently in Latin Americans and Asians. Treatment is not standardized. OBJECTIVES: To identify subtypes, demographic and clinical features and treatment efficacy in patients with histopathologically confirmed PLCA. MATERIALS AND METHODS: Data of PLCA patients were extracted from the electronic hospital database and included if diagnosis of PLCA was histopathologically confirmed and if sufficient information regarding treatment and follow-up was available. The evaluation of the treatment efficacy was based on a novel score to assess the reduction of itch and skin lesions. RESULTS: In this retrospective, monocentric study, 37 cases of PLCA diagnosed between 2000 and 2020 were included (21 females) with a mean age of 52 years. LA was the most frequent subtype found in 21 patients (56.8%), followed by MA in 10 patients (28%) and BA in 6 patients (16.2%). No cases of NA were included. 22 patients (59.4%) had skin phototype II or III. Regarding treatment, a combination of UVA1 phototherapy with high-potency topical corticosteroids seemed to show the highest efficacy with complete clearance of symptoms in 4 patients (10.8%). A substantial improvement of symptoms was found in 5 patients (12.7%) treated with high-potency topical corticosteroids alone or in combination either with UVA1 or bath PUVA or monotherapy with UVA1 phototherapy or capsaicin (0.075%) cream. Low-/medium-potency topical corticosteroids alone or in combination with UVBnb (311 nm) phototherapy showed a lower efficacy. CONCLUSION: Our data show that PCLA is a rare disease in central Europe but can also be expected in a predominantly Caucasian population. The best treatment response was achieved with a combination of UVA1 phototherapy and high-potency topical corticosteroids.