Tumor necrosis factor-α (TNF-α) normally binds to TNF-α receptors, leading to the inflammatory response of autoimmune diseases. Adalimumab is a TNF-inhibiting, anti-inflammatory, biological medication which binds to TNF-α, thus reducing this inflammatory response. The use of TNF-α-inhibiting medication, such as adalimumab, being the first FDA-approved treatment for hidradenitis suppurativa, has drastically changed the management of dermatological diseases. One rarely reported manifestation that occurs as a side effect associated with the use of TNF-α-blocking agents is erythroderma. This study, for the first time, reports the case of a patient suffering from hidradenitis suppurativa with concomitant psoriasis, who developed a severe and acute erythrodermic rash after the start of adalimumab therapy.