fatty acid supplements may show benefit in reducing itch. Adverse effects Each class of abirritants has its own set of potential adverse effects. Systemic Corticosteroids Systemic corticosteroid use has been associated with a wide range of potential adverse effects. In a review article, the following common complications were noted for prolonged use: redistribution of fat tissues (moon face), high blood sugar, infections, delayed wound healing, and HPA axis suppression, where the body's natural production of hormones like corticotropin-releasing hormone and adrenocorticotropic hormone is suppressed as a response to the increased level of corticosteroids in the blood. There is a lack of data on adverse effects associated with corticosteroid use of a shorter period and lower dose. Topical Corticosteroids Both local and systemic side effects can result from topical corticosteroid use, especially in prolonged treatment. Local side effects can occur regularly from prolonged use, which include skin atrophy (thinning), stretch marks, infections, lighter skin color, and sudden decrease in efficacy of the drug. Systemic side effects are far less prevalent than local ones. Prolonged high potency corticosteroids use on thin skin, especially in children, increases the risk of systemic side effects since thin skin allows for greater absorption. One commonly cited systemic side effect from topical use is HPA axis suppression. A meta-analysis of topical corticosteroid use in children concluded that low-potency corticosteroid at recommended dosages and duration do not cause clinically significant HPA suppression. Antihistamines Antihistamines target the molecule histamine by blocking the histamine H1 receptor. First-generation antihistamines like diphenhydramine and chlorpheniramine are able to move from the blood into the brain across the blood–brain barrier, where they block the H1 receptor, reducing the neurotransmitter effect of histamine, leading to central nervous system side effects such as drowsiness and confusion. Second generation antihistamines, such as fexofenadine and cetirizine are less able to move from blood circulation into the brain and are therefore associated with fewer side effects in usual doses. μ-opioid receptor antagonists μ-opioid receptor antagonists are usually well-tolerated and have no abuse potential since they do not cause physical dependence. Side effects are dose-dependent and generally limited to the first two weeks of treatment. Opioid withdrawal symptoms are rare and may include severe lightheadedness, depersonalization and anxiety. Antidepressants Serotonin reuptake inhibitors, including both serotonin-norepinephrine reuptake inhibitors (SNRIs) and selective serotonin reuptake inhibitors (SSRIs), are generally well tolerated. Common side effects include: Sexual dysfunction, which is the most common side