Could leakage of a saline and capsule implant cause a skin rash?

Not quite sure of the progression of issues. did you have replacement? It sounds like you did not. Then I must assume the leaking saline has become fungal contaminated!!! Or worse. Best to have immediate removal and culture of any fluids in the implant pockets... 

Thanks for your interesting question.It is not uncommon for saline breast implants to have ruptures or even slow leaks after many years.  Over time the implant shell can develop a small defect causing the saline solution to leak and for your breast to lose volume.  I don't believe that this would be related to a skin rash.  In any case I do recommend that you seek the opinion of a dermatologist regarding your skin concerns.  Once that is addressed it is reasonable to consider exchange of your current implant for new ones, or another procedure to address any concerns you may have regarding your breast.Best Wishes