Inhibition of irritation and contact hypersensitivity by ethacrynic acid

The immunosuppressive effect of topical ethacrynic acid (ECA) was tested on both the induction and elicitation phases of contact sensitization in a mo use model, ECA (0.5% in vehicle) reduced the sensitization response by >50% when the sensitizer was either dinitrochlorobenzene (DNCB), oxazalone (OX) or para-phenylenediamine (PPD), and was applied 1 day later to the ECA-pre treated skin site, The immunosuppressive effect of combining ECA with eithe r hydrocortisone or with cis-urocanic acid was also tested. An additive sup pressive effect was observed with ECA in both combinations. The effect of E CA (1% in vehicle) on blocking the elicitation phase was also examined in a mouse ear edema assay. ECA was highly effective in preventing the challeng e response in mice previously sensitized to either DNCB, OX or PPD, ECA (1% in vehicle) was also tested for its ability to inhibit contact irritation, ECA (1% in vehicle) was highly effective in preventing ear edema due to to pically applied skin irritants including arachidonic acid, capsaicin, lacti c acid, phorbol myristate acetate, trans-retinoic acid, and sodium lauryl s ulfate, ECA may be useful for both prophylaxis and therapeutic treatment of diverse skin conditions including contact dermatitis, eczema, and other re lated allergic skin disorders.