[Argyria cutis following colloidal silver treatment in two patients with in situ melanoma].

Prior to the discovery and popularization of antibiotics, silver colloidal derivatives were widely used, mainly for the treatment of infections, due to their possible antibacterial and antiviral activity. The silver colloid solution contains microscopic silver particles suspended in a colloidal base. Although there are no clinical trials or reliable literature to prove its efficacy, the increasing interest in alternative and natural remedies has been accompanied by a parallel increase in the indication of silver colloid use for the treatment of various pathologies and for preventive purposes. In the following case reports, the authors detail the case of two male patients who developed in situ neoplastic skin lesions and consumed a daily silver colloid solution on the advice of a naturopath for malignancy prevention. The skin lesions showed no change but argyria has occurred in the skin and nailbed. The aim of this case report is to draw attention to the potential toxicity of silver colloid. The assessment of effectiveness of this therapy is not possible because the in situ neoplastic lesions (lentigo maligna melanoma and superficial spreading melanoma) without any treatment may stay in a preinvasive stage for decades. Orv Hetil. 2025; 166(13): 511–515.