Macular amyloidosis pigmentation- melanin or something else, an insight into amyloid – melanin connection

Macular amyloidosis  represents a common variant of primary localized cutaneous amyloidosis (PLCA) which  was first described by Palitz and Peck in 1952. Clinically, it  presents as poorly delineated hyperpigmented patches of grayish-brown macules with a rippled pattern, associated with deposition of amyloid material CYTOKERATIN- 5 in the papillary dermis distributed predominantly over  the interscapular area and extremities (shins and forearms) . Etiopathogenic factors - race, female gender, genetic predisposition (OSMR and IL31RA mutations), sun exposure, atopy and friction have been implicated. 

Our aim was to find out the melanin content and melanin index in the lesions of Macular amyloidosis and to incure whether melanin an plays important role in pigmentation of macular amyloidosis.  46 patients of macular amyloidosis of age group 18-40 yrs. were selected including 30 females and 16 males , Mexameter MX18 was used to measure melanin content and melanin index in the lesions of Macular amyloidosis over upper back and non-affected similar areas. Data was collected, fed into excel sheets and results were inferred.

Melanin index was raised in all the patients of cutaneous amyloidosis as compared to non-affected region of upper back where the ‘p’ value came out to be significant i.e. <0.05 in both males and females.

This study is first of its kind to evaluate the cause of pigmentation in cutaneous amyloidosis, Recent studies in melanoma have shown that amyloid acts as a precursor and accelerates the process of melanogenesis. Similar phenomenon may also exist in primary cutaneous amyloidosis. We recommend the use of strong antimelanotic agents and lasers in the treatment of macular amyloidosis.