@lorraine06 - I debated for a while whether or not to share my experience. I'm sharing this in the hopes that it "might" be helpful. THIS IS NOT MEDICAL ADVICE, AND MIMICKING THIS IS NOT RECOMMENDED.

I have these dark spots on my lower arm outside area, and it's been there for 20 years. Most of the time I assumed it was due to sunburn, as this is the exposed surface of the arm. In the past 5 years, at least 4 dermatologists have gone to, most of them sold their expensive products from their pharmacies. One even did a biopsy to tell this has happened due to my scratching. The dark spots (hives) kept on increasing and along with the itchiness. I had all hopes lost.

This is when I met a Skin care specialist in India. Within 10 minutes, he diagnosed I have Macular Amyloidosis condition, and this can be cured but the treatment needs to be established after some trials. I didn’t believe him, because I'm used to doctors around here ordering a number of tests before determining the illness. The doctor then told me that because of this illness, I should have a dark-colored hive in my back. Then we examined my back and discovered a hive on the top of my back.

Because I was only there for a brief period of time and chose only one choice, I did not have the opportunity to try other options. There has been no irritation so far, and the black patches have decreased by 10%. I realize it's taking longer than I anticipated, but I've had this for 20 years. When I return to India next year, I hope to pay him another visit and stay a little longer this time.

This is the medication he gave me: Colchicine

A cream to suppress itchiness (Clobetasol Propionate). Using this cream, he created a moisturizer which I apply after everyday shower.

I take Colchicine pill with breakfast.

Other Recommendations given to me:

Use mild shower gel or hand wash to wash the arms.

Do not use scrub on the arms or the affected areas.

Eat healthy food.

Warning:

This pill can cause boils in the mouth, and it happened to me. I had to stop it for a week, then I started lower dosage (1 pill in 2/3 days) and now I am taking it every day. Doctor had given me 90 day supply. Now, my US primary physician has given me another 90 days prescription and am continuing to take .it

Looks like Macular Amyloidosis is common in south Asians. Also, my US Physician questioned me about this pill since most of the papers predominantly states it is recommended for gout. Here is the paper which mentioned this pill can be used for Macular Amyloidosis.
https://emedicine.medscape.com/article/1093258-medication