Hello, Welcome to healthcare magic, From your description it seems like you are having idiopathic guttate hypomelanosis. It is a very benign condition and won t become large like vitiligo or leukoderma. It will remain as a small sized white lesion. The exact cause of this is not known, long term exposure to sunlight is hypothesized as a cause and thus it may be an ageing sign. You may leave it alone . It is not contagious. Medical line of treatment is topical steroids which you had tried already with no success. If you want it to be removed, go for procedures like dermabrasion, cryo, cautery or ablative fractional laser. You should consult a dermatologist practising cosmetic dermatology for this. Hope this helped, Take care.