Dirty Papules and Plaques in Skin of Color: New Observations by Dermoscopic Dissection

Confluent reticulated papillomatosis (CRP), terra-firme-forme-dermatitis (TFFD), and dermatitis neglecta (DN) are the benign, acquired conditions that present with dirty-looking hyperpigmented and hyperkeratosis lesions on neck, back, and truncal areas. They pose difficulty in diagnosis because of their clinical similarities and thereby in treatment approaches. Bedside test and histopathology is helpful in the diagnosis. Dermoscopy is utilized as an evidence-based diagnostic method.

To evaluate and to compare the dermoscopic patterns among CRP, TFFD, and DN and to correlate them in terms of histopathological features.

It was a cross-sectional observational study with a total of 62 patients, among whom 30 were CRP, 20 had TFFD, and 12 were diagnosed as DN. Clinical and dermoscopic evaluation was done in all patients, and histopathology was carried out in selective cases to confirm the diagnosis.

Global view of dermoscopy in CRP revealed a cerebriform pattern. The arrangement of pigment globules was characteristic in CRP, TFFD, and DN, giving a "cobblestone," "mosaic," and "cornflake-like" appearance, respectively. The color of the pigment globules was strikingly significant. Yellow globules were predominant in CRP and TFFD, having p values of 0.001 and 0.004, respectively. Scales were conspicuously present in CRP, with a statistically significant p value of 0.003. Focal white areas and hair changes were observed in CRP alone, whereas black dots were found only in TFFD.

Dermoscopy acts as an in vivo and a noninvasive, rapid technique in the diagnosis of clinically look-alike conditions. It demonstrates characteristic features in CRP, TFFD, and DN. Thus, it is an evidence-based diagnostic method that assists the treating physician in daily clinical practice.