This patient has atopic dermatitis (AD), but on the basis of the image and description above, by no means would this be an intuitive diagnosis; the findings are not characteristic of those in younger patients with AD. Further, clinicians might find it difficult to diagnose AD in an older patient because older patients generally tend to have more comorbidities and medication side effects, including chronic pruritus of unknown origin and xerosis, which could confound the diagnosis.
Finally, specific guidelines are lacking for clinicians to distinguish AD from other pruritic skin conditions in the older patient. Currently, according to one report, older patients are diagnosed with AD after at least 6 months of symptom assessment and exclusion of other conditions, including cutaneous T-cell lymphoma, allergic contact dermatitis, psoriasis, drug reactions, and chronic idiopathic or secondary erythroderma.
AD arising de novo in older persons is a discrete form of the disease that characteristically involves the face, neck, trunk, and hands, while sparing the flexural areas, which are prominently involved in younger patients. The eczema can become erythrodermic. Older men are affected threefold more often than older women.
Skin manifestations in older patients with AD generally match those of adolescents and young adults with AD, but the reverse sign of lichenified eczema around unaffected folds of the elbows and knees is more common than the classic sign of localized lichenified eczema at those folds.
Factors rendering older people susceptible to AD include innate physiologic changes of aging, notably a decline in skin barrier function, dysregulation of innate immune cells, and skewing of adaptive immunity to a Th2 response.
Much about how to best treat AD in older patients remains unclear. It is a challenge to treat older patients according to standardized guidelines for general AD treatment because dermatologists and others need to consider comorbidities and the medications that these patients might already be taking. Some examples: Dermatologists might limit cyclosporine use in patients with hypertension and reduced kidney function, or limit systemic steroid use in patients with osteoporosis. Older patients have a greater propensity for infection, which might cause dermatologists to limit systemic immunosuppressant drugs. And skin thinning and diffuse photoaging might cause doctors to limit even topical steroid treatment in these patients.
As in other age groups, regular application of moisturizers in combination with calcineurin inhibitors, adjunctive administration of oral antihistamines and avoidance of exacerbating factors comprise basic treatments for AD in older patients.
Although antihistamines such as hydroxyzine can work for itching in some individuals, they are generally lacking in efficacy in most patients with AD.
Brian S. Kim, MD, is Associate Professor, Department of Medicine, Division of Dermatology, Washington University School of Medicine, St. Louis, Missouri
Brian S. Kim, MD, has disclosed no relevant financial relationships.