Dermoscopic Pigment Network: Characteristics in Non-melanocytic Disorders

Dermoscopy aids in differentiating café-au-lait macules from congenital melanocytic nevi in patients with darker skin phototypes

Dermoscopy aids in the diagnosis and management of pigmented growths and disorders of pigmentation in children. However, there is limited literature on the dermoscopic appearance of café-au-lait macules (CALMs) and congenital melanocytic nevi in patients with dark skin. We report two cases of young children with dark skin and many hyperpigmented patches in whom dermoscopy was utilized to accurately diagnose CALMs and facilitate testing for neurofibromatosis.

Can we predict postinflammatory hyperpigmentation after laser treatment based on dermoscopic findings of solar lentigo?

Solar lentigo (SL) commonly occurs as hyperpigmented macules in areas exposed to ultraviolet radiation. It typically shows an increased number of melanocytes in the basal cell layer of the skin, with or without elongated rete ridges. This retrospective study aimed to evaluate the characteristic dermoscopic patterns, reflecting different histopathological features, which might be valuable in predicting the possibility of postinflammatory hyperpigmentation (PIH) occurring after laser treatment. In total, 88 Korean patients diagnosed with biopsy-proven SL (a total of 90 lesions were diagnosed) between January, 2016 and December, 2021 were included. Histopathological patterns were classified into six categories. Dermoscopic features were classified into six categories. Pseudonetwork pattern and rete ridge elongation showed a statistically significant negative correlation. This means that a flatter epidermis is likely to manifest as a pseudonetwork pattern. The erythema pattern showed a significant positive correlation with interface changes and inflammatory infiltration. Bluish-gray granules (peppering), a characteristic dermoscopic finding, showed significant positive correlations with interface changes, inflammatory infiltration, and dermal melanophages. Clinicians considering laser treatment for patients with SL should perform dermoscopic tests before treatment. The pseudonetwork relates to flattened epidermis and fewer Langerhans cells; thus, a lower remission of PIH after laser treatment might be expected. If bluish-gray granules or erythema are observed, inflammatory conditions are likely to be involved. In such cases, regression of the inflammatory response through drug therapy, such as topical corticosteroids, should be a priority option before laser treatment.

A Comparative Study of Dermatoscopic Features of Acne-related Postinflammatory Hyperpigmentation in Facial and Nonfacial Areas in Asian Patients

BACKGROUND

Postinflammatory hyperpigmentation (PIH) is a common problem, especially in patients with darker skin tones. It can occur on any area of the body following external injuries or intense inflammatory conditions. However, there is limited evidence regarding the differences in dermatoscopic patterns between facial acne-related PIH and nonfacial acne-related PIH.

OBJECTIVE

We sought to determine the dermatoscopic features of acne-related PIH in facial and nonfacial areas in an Asian population.

METHODS

Patients with acne-related PIH in both facial and nonfacial areas were enrolled. Baseline demographic data, location, and duration of PIH were recorded. Dermatoscopic and clinical pictures of each patient were taken from the darkest PIH lesions of both areas. Differences in dermatoscopic patterns were analyzed.

RESULTS

Fifty patients were enrolled. The mean age was 26.74 (+ 6.75) years, and the Fitzpatrick Skin Types were III (66%) and IV (34%). In terms of morphological patterns of melanin, nonfacial PIH showed a significantly more regular pigment network than facial PIH (100% vs. 20%, p<0.05), while facial PIH exhibited a more pseudoreticular pigment network than nonfacial PIH (70% vs. 0%, p<0.05). In terms of vascularity, facial PIH demonstrated more telangiectasia and an increased vascular component compared to nonfacial PIH (56% vs. 16%, p<0.05). Moreover, hypopigmentation within the PIH lesion was demonstrated in both facial and nonfacial lesions (42% vs. 50%, p=0.541).

CONCLUSION

Acne-related PIH in facial and nonfacial areas showed different morphological pigment patterns and degrees of vascularity. Dermatoscopic examination should be performed before treatment initiation.