Atypical Dyschromia in Skin of Color.

Dyschromia is a concern for many patients, especially persons of color. Postinflammatory hypopigmentation and depigmentation can affect all skin types; however, it is more apparent in those with darker skin. Some members of the dermatology community may not comprehensively understand the mechanisms of these reactions and the extent of the psychosocial effect they have on persons of color. Skin of color patients experiencing a decrease or loss of pigmentation are left with few treatment options, with no available evidence-based treatment established from a sufficient sample size. Several diseases may present with hypopigmentation and/or depigmentation despite this not being a major criterion for these conditions, including atopic dermatitis, lichen planus, discoid lupus erythematosus, polymorphous light eruption, and scleroderma. Here, we present three cases of atypical dyschromia in skin of color to highlight the underlying hypo- and depigmentation that may present with active disease and persist despite appropriate treatment.  Practice Points: 1. These cases foreground the potential for a range of dermatologic conditions to result in atypical pigment changes in persons of color. 2. Postinflammatory hypopigmentation or depigmentation may persist in skin of color despite the regression of active disease.J Drugs Dermatol. 2024;23(2):100-102.     doi:10.36849/JDD.7683.

Diagnosing Disorders of Hypopigmentation and Depigmentation in Patients with Skin of Color.

Skin hypopigmentation and depigmentation disorders are a top concern for patients with skin of color seeking care from a dermatologist. The visual contrast between involved and uninvolved skin in these disorders makes them particularly burdensome for patients with skin of color. These disorders may have a wide differential of diagnosis, as patients with skin of color may present differently or more frequently than White patients for certain conditions. Clues from a comprehensive history and physical examination with standard lighting and a Wood's light are essential for clinching the diagnosis, although a biopsy may be warranted in special cases.

Basement membrane thickness helps to differentiate hypopigmented mycosis fungoides from clinical and pathological mimickers.

BACKGROUND: Hypopigmented mycosis fungoides (HMF) is a relatively rare subtype of mycosis fungoides (MF). The diagnosis of HMF can be quite challenging in case of insufficient diagnostic criteria due to the diverse conditions that present with hypopigmented lesions. This study aimed to evaluate the usefulness of the assessment of the basement membrane thickness (BMT) in the diagnosis of HMF. METHODS: A retrospective study was conducted on biopsy specimens of 21 HMF and 25 non-HMF cases who presented with hypopigmented lesions. The thickness of the basement membrane was evaluated in periodic acid-Schiff (PAS)-stained sections. RESULTS: The mean BMT was significantly higher in the HMF group than in the non-HMF group (P < 0.001). The best cut-off value of mean BMT for the detection of HMF verified in ROC analysis was 32.7 µm (P < 0.001) with a sensitivity of 85.7% and a specificity of 96%. CONCLUSION: Evaluation of BMT can be a useful tool to distinguish HMF from other causes of hypopigmented lesions in doubtful cases. We suggest the use of " BMT more than 33 µm" as a histopathologic criterion of HMF.

Adolescent extra-truncal progressive macular hypomelanosis.

Two adolescent females presented to outpatient clinic with isolated, non-scaly, asymptomatic hypopigmented macules and patches on the arm(s). Both cases had Wood's lamp exams notable for extralesional punctiform coral-red perifollicular fluorescence on the back and faint intralesional enhancement. In one case, biopsy was performed and deemed consistent with progressive macular hypomelanosis. The patient had complete response to antimicrobial therapy and sun exposure.