SyStemic contAct DermAtitiS

22 January 2012 | Skin & Aging | www.skinandaging.com Allergic Contact Dermatitis (ACD) is an important disease that affects 14.5 million Americans each year. The economic impact of this condition is high, whether measured by patient morbidity, health care expenditures, loss of income or lost time from school and work. Once patch testing is performed and an allergen source has been identified, education becomes the critical intervention to ensure adherence to an avoidance regimen. With allergen avoidance, remission of the dermatitis ensues. Patients who are unable to comply with allergen avoidance are at risk for recurrent or sustained dermatitis or progression to a systematized presentation. In fact, patient education often begins before the diagnostic patch tests are ever placed, to ensure that ACD patients have an appropriate understanding of potential outcomes and the central role patients play in both their disease and treatment. During the initial consultation, patients are often taught about the delayed presentation of ACD and its relationship with the immune system (sensitization to a chemical and elicitation of a dermatitis with re-exposure). Furthermore, they are instructed that it may develop at any point in time, even to something that the patient has been using regularly for a short period of time or intermittently for years. In certain cases, other related disorders such as irritant contact dermatitis (ICD) and contact urticaria (CU) may be relevant; history, rather than patch testing, can point to these as the correct diagnosis for the patient. It is important to note that ICD, the most prevalent form of contact dermatitis, can, at times, precede or occur concomitantly with ACD. Unlike ACD, ICD is not immunemediated. It occurs secondary to contact with an irritating or abrasive substance. CU, on the other hand, represents the least prevalent form of ICD. The wheal and flare reaction of CU is an IgEand mast cell-mediated immune phenomenon of immediatetype hypersensitivity. Although this form of contact reaction is rare, it is important to recognize because of its potential to produce serious anaphylactic-type reactions. This column highlights ACD, focusing on significant allergens, regional presentations of dermatitis and topic-based allergic manifestations and offers clinical tips for diagnosis and treatment. This month, we feature an uncommon but especially important category of allergic dermatitis — systemic contact dermatitis.