Study Considers Mnemonic Devices for the Diagnosis of Psoriasis

Mónica Roncero-Riesco, MD

A new investigation into mnemonic devices for dermatology care found that the ñ sign could be used for dermatology and pathology residents and physicians in distinguishing between psoriasis and other inflammatory skin disorders.

Investigators noted that the histopathologic diagnosis of inflammatory skin disorders could prove challenging, with psoriasis being particularly heterogeneous and dynamic.

Classical histologic results can be markedly different throughout the clinical evolution of psoriasis. Skin biopsies of the disease includes regular epidermal hyperplasia, elongation of the rete ridges with a thin parapapillary epidermis, dilated vessels, and hyperkeratosis.

Investigators observed that the union of 2 well-established histologic criteria for psoriasis, fragmentation and separation of the laminar parakeratotic stratum corneum and epidermal hyperplasia with elongation of the rete ridges, resembles the lowercase ñ in the modern Latin alphabet.

As such, a team led by Mónica Roncero-Riesco, MD, Cabueñes University Hospital, detailed the potential use of the ñ sign as a visual clue for the diagnosis of psoriasis.

The Methods

The team utilized data on selected lesion biopsy specimens from patients in the hospital data bank with a previous histologic diagnosis of psoriasis or a previous diagnosis of an inflammatory skin disorder other than psoriasis.

From there, 2 investigators analyzed the biopsy specimens simultaneously in random order to determine the presence of the ñ sign. A statistical analysis was performed shortly after.

The Findings

The investigators evaluated biopsy specimens from a total of 136 patients, 67 of whom had a previous histologic diagnosis of psoriasis and 69 who had a previous diagnosis of an inflammatory skin disorder other than psoriasis.

Specifically, 29 patients had eczema, 11 pityriasis lichenoides, 12 with pityriasis rosea, and 17 with chronic lupus erythematous.

Investigators observed that the ñ sign was present in lesion biopsies from 54 of 67 patients with psoriasis (80.6%) ad from 1 of 69 patients in the control group (1.5%).

Roncero-Riesco and colleagues noted that mnemonics are useful when first-sight recognition is not possible, and that visual cues such as the ñ sign can facilitate reaching a final diagnosis in dermatopathology.

The limited number of cases and controls in the single-center study urged the team to recommend more extensive studies to determine the sensitivity and specificity of the ñ sign in addition to its predictive values.

“These findings are not specific to psoriasis and can be observed separately in other inflammatory skin conditions such as pityriasis lichenoides or subacute eczema,” the team wrote. “However, the sum of both criteria (ie, the ñ sign) is a distinctive histologic finding of psoriasis.”

The study, "The ñ SignA Visual Clue for the Histopathologic Diagnosis of Psoriasis," was published online in JAMA Dermatology.