A patient with psoriasis was staed on systemic steroids. After stopping treatment patient developed generalized pustules all over his body, the most likely cause is:

Pustular psoriasis is another variant of psoriasis. Patients may have disease localized to the palms and soles, or the disease may be generalized. Regardless of the extent of disease, the skin is erythematous with pustules and variable scale. Localized to the palms and soles, it is easily confused with eczema. When generalized, episodes are characterized by fever (39deg-40deg C) lasting several days, an accompanying generalized eruption of sterile pustules, and a background of intense erythema; patients may become erythrodermic. Episodes of fever and pustules are recurrent. Local irritants, pregnancy, medications, infections, and systemic glucocoicoid withdrawal can precipitate this form of psoriasis. Oral retinoids are the treatment of choice in nonpregnant patients. Ref: Harrison's Internal Medicine; Pa 2. Cardinal Manifestations and Presentation of Diseases ; Section 9. Alterations in the Skin ; Chapter 53. Eczema, Psoriasis, Cutaneous Infections, Acne, and Other Common Skin Disorders ; Eczema and Dermatitis.