Lichen amyloidosis and macular amyloidosis patients in a tertiary dermatology centre in Singapore : a 4-year retrospective review

الملخص EN

Introduction : Lichen amyloidosis (LA) and macular amyloidosis (MA) are uncommon chronic skin conditions which are more frequent in the Asian population.

Materials and Methods : To find associations as well as record the presence/absence of pruritus, we collected retrospectively all cases (1210) of clinically diagnosed LA (948) and MA (262) from 2004 to 2007 attending the National Skin Centre outpatient clinic.

Results : The mean age at presentation was 51 years old.

51 % of patients had pruritus.

Differences between LA and MA were statistically significant (LA to MA odds ratio = OR) regarding sex (males more likely : OR = 1.9), race distribution (Chinese : OR = 2.1) and in skin diseases, chronic urticaria (OR = 2.3) and lichen simplex chronicus (OR = 14.3).

Conversely pruritus was more associated with MA : (MA/LA odds ratio = 1.3).

In 29 cases contact dermatitis was recorded and in 7 cases, allergic contact dermatitis was confirmed, with positive patch tests to nickel, gold, neomycin and flavin.

In 3,22 % and respectively 0.33 %, LA/MA was associated with chronic idiopathic urticaria and acute urticaria.

Conclusions : In this the first study separating LA from MA, we have observed significant differences.

Although LA/MA is more frequent in females, odds suggest that male Chinese are more likely to have LA than the other racial groups in Singapore.

Also pruritus is more associated with LA than MA.

LA/MA is unlikely to have a causal relationship with urticaria.

Further studies regarding the timing and intensity of pruritus in relation with the development LA/MA are needed.

This should be compared with a control group of patients with eczema only.