A prospective, clinicopathologic study involving 268 patients with biopsy-proven basal cell carcinoma, squamous cell carcinoma, malignant melanoma, or melanoma in situ “revealed that pain is associated with histologic features that involve deeper dermal processes in [squamous cell carcinoma] lesions, such as ulceration and depth of invasion, whereas itch is linked with the more superficial [basal cell carcinoma] lesions.” The study by Gil Yosipovitch, MD, of the Department of Dermatology and Temple Itch Center, Temple University School of Medicine, Philadelphia, and colleagues was published in JAMA Dermatology.
The authors concluded, “These findings support the theory that itch emanates from the upper layers of the skin, whereas pain is associated with deeper processes.” The investigators also stated that the study “highlights the importance of a simple bedside evaluation for the presence and intensity of pain and itch as an easily implementable tool for physicians to use when evaluating suspicious skin lesions.”
Drawn from the patient population presenting to the Department of Dermatology surgical unit at Wake Forest University Baptist Medical Center in Winston-Salem, North Carolina, from July 1, 2010, through March 31, 2011, the study participants represented 339 histologically confirmed cutaneous neoplasms: 166 basal cell carcinomas, 146 squamous cell carcinomas, and 27 melanomas. The participants completed questionnaires assessing itch and pain intensity of their skin tumors at the time of excision. Histopathologic analysis for each neoplasm included assessment of the amount and type of inflammation, ulceration, perineural invasion, and depth of invasion.
Across all types of skin cancers, itch was prevalent in 36.9% and pain in 28.2%. “The prevalence of itch was greatest in [squamous cell carcinoma] (46.6%), followed by [basal cell carcinoma] (31.9%) and melanoma (14.8%). Pain prevalence was also greatest in [squamous cell carcinoma] (42.5%), again followed by [basal cell carcinoma] (19.9%) and melanoma (3.7%). The prevalence of itch and pain was significantly greater in [squamous cell carcinomas] (P = .002) and [basal cell carcinomas] (P < .001) compared with melanoma,” the researchers reported.
Grouping all skin cancers together, the mean depth of invasion was highest in the most painful lesions and lowest in the painless lesions. “Pain intensity was significantly associated with the degree of inflammation (mild or none vs moderate or marked; P < .001), presence of neutrophils in the inflammatory infiltrate (predominantly mononuclear vs mixed or neutrophilic; P = .003), presence of eosinophils (present vs absent; P = .007), ulceration (yes vs no; P = .003), perineural invasion (yes vs no; P < .001), depth of invasion (P = .001), and largest diameter length of skin lesion (P < .003), the researchers reported.
“Itch intensity was significantly associated with the degree of inflammation (mild or none vs moderate or marked; P = .001) and the presence of eosinophils (present vs absent; P = .02),” they added.
The authors acknowledged that the relatively small sample size of melanoma cases “does not allow us to draw firm conclusions about the association between pain and itch and histopathologic features of melanoma. However, it is clear that melanomas have a significantly decreased prevalence of pain and itch compared with nonmelanoma skin cancer, a finding confirmed by a similar study that examined itch and tenderness in patients with melanoma,” the investigators noted. ■
Yosipovitch G, et al: JAMA Dermatol. July 23, 2014 (early release online).