Lupus nephritis is a severe complication of systemic lupus erythematosus, with ultraviolet-induced injury acting as a critical trigger for its onset. Given that previous theories have seldom specifically addressed its fulminant nature and skip-stage transmission characteristics, this study uses classic literature to propose a core pathogenesis hypothesis stating that sunlight-triggered latent toxins, causing a direct invasion into weifen and xuefen, ultimately accumulating in the renal collaterals. This hypothesis posits that the solar fire resonates with the latent toxins concealed within the body, causing the pathogenic toxins to deviate from regular transmission pathways, rapidly breach the exterior defense, directly bypass the qifen, deeply invade the yingfen and xuefen, and bind within the systemic blood collaterals. Based on this transmission pattern, our team integrated Xin′an medical theory to establish a three-stage interceptive treatment strategy. During the triggering stage, characterized by the simultaneous involvement of the weifen and xuefen, treatment focuses on resolving weifen and xuefen, venting macules, and intercepting toxins with the modified self-formulated Touban Jiedu Formula, which includes Fuping (Spirodelae Herba), Zicao (Arnebiae Radix), and Mudanpi (Moutan Cortex). In the fulminant stage, where stasis and toxins bind in the collaterals, the aim is to search out and unblock collaterals using insect medicinals, resolve stasis, and attack accumulations with the modified self-formulated Soufeng Jiedu Formula, using Chantui (Cicadae Periostracum), Quanxie (Scorpio), and Jiangcan (Bombyx Batryticatus). Finally, for the protracted stage marked by healthy qi deficiency with lingering toxins, the emphasis is on dual supplementation, venting pathogens, and supporting healthy qi via a combination of modified Shenqi Dihuang Decoction and Qinghao Biejia Decoction, highlighting raw Huangqi (Astragali Radix), Qinghao (Artemisiae Annuae Herba), and Biejia (Pelodisci Carapax).