EXPERT ANALYSIS FROM PDA 2015
PARK CITY, UTAH (FRONTLINE MEDICAL NEWS) – When an otherwise healthy 75-year-old patient presents with persistent pruritus as the chief complaint, the first thing to do is rule out specific dermatologic disorders, according to Dr. Kevin C. Wang.
“Thankfully, most of the patients complaining of pruritus have visible dermatoses,” Dr. Wang said at the annual meeting of the Pacific Dermatologic Association. “According to a review of more than 150 elderly patients in the outpatient setting who presented with a chief complaint of persistent pruritus, the five most common diagnoses were atopic-like dermatosis, lichen simplex chronicus/prurigo nodularis, subacute prurigo, transient acantholytic dermatosis, and neuropathic disease.”
Treatment directed at the primary element triggering the pruritus is most effective. “The best treatment for these patients will likely involve multiple modalities/combination therapy, as there is no one major pathway pathophysiologically,” said Dr. Wang of the department of dermatology at Stanford (Calif.) University and the Palo Alto VA Hospital.
“Pruritus can be quite debilitating,” said Dr. Wang, who also is the principal investigator of a research lab at Stanford. “I have not met an itchy patient who has said that it has not ruined their lives somehow: whether it’s their work, social life, things that they like to do. Also, many elderly veterans are already quite debilitated functionally in the first place, so it is a huge problem.”
An estimated 2% of all dermatology visits are for pruritus, “but it’s probably more than that, because a lot of those complaints don’t come up until you ask the patient in person,” he said. “This issue is also important because as physicians we really don’t have any specific ‘itch blockers.’ We just use drugs developed for other conditions that happen to work, but not often enough.”
Dr. Wang then went on to share some of the concepts raised in a 2011 article by Dr. Timothy G. Berger and Dr. Martin Steinhoff of the University of California, San Francisco. They suggested that pruritic conditions afflicting the elderly are the results of a variety of age-related changes they termed “eruptions of senescence” (Semin Cutan Med Surg. 2011;30:113-7).
As people age, Dr. Wang said, the immune system “becomes much more proinflammatory, including significant aberration of T- and B-cell populations. More importantly, the immune system develops an allergic Th2 phenotype, where you have loss of naive T cells as the immune repertoire becomes populated with ‘committed’ T and B cells, and a preponderance of Th2 cells. This means you have an impaired ability to respond to new antigens, with a greater propensity for autoimmune responses, and lingering, low-grade inflammation.”
Aging also brings structural changes to the epidermal barrier, he continued. Specifically, the surface pH becomes less acidic. This is problematic because enzymes that are required to process lipids function best at acidic pH. “You also have a reduction in the rate of barrier repair, and decreased production of filaggrin and aquaporin-3,” he said. “In combination, this impaired barrier has two direct consequences: Barrier failure may lead to increased development of contact dermatitis, because the impaired barrier may not prevent penetration of potential antigens into the epidermis, and when the barrier fails, the cytokines released to induce barrier repair are proinflammatory, resulting in dermatitis.”
He reported having no financial disclosures.