The term rupioid has been used to describe well-demarcated, cone-shaped plaques with thick, dark, lamellate, and adherent crusts on the skin that somewhat resemble oyster or limpet shells. We present a case of rupioid psoriasis that was treated with methotrexate, topical steroids, and intralesional steroid injections. Rupioid manifestations have been clinically observed in a variety of disease settings, including rupioid psoriasis, reactive arthritis, disseminated histoplasmosis, keratotic scabies, secondary syphilis, and photosensitive skin lesions in association with aminoaciduria. To diagnose the underlying infectious or inflammatory diseases beneath the thick crusts, skin biopsy and a blood test for syphilis may be necessary. Our aim is to familiarize clinicians with the differential diagnoses for skin diseases with rupioid manifestations.