Drugs such as lithium, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, interferons, nonsteroidal antirheumatic drugs, and antimalarials may cause the onset or worsening of pre-existing disease, just as abrupt discontinuation of systemic corticosteroids may exacerbate plaque or pustular psoriasis [25]. This evidence concerns the gene ACE and pustular psoriasis.