Ashy dermatosis, lichen planus pigmentosus and pigmented cosmetic dermatitis: Are we splitting the hair?

Acquired dermal macular hyperpigmentation: an overview of the recent updates

Acquired dermal macular hyperpigmentation (ADMH), previously known as macular pigmentation of uncertain etiology (MPUE), is an umbrella concept that unifies the distinct but overlapping acquired dermal pigmentary disorders like lichen planus pigmentosus, ashy dermatosis, erythema dyschromicum perstans, Riehl's melanosis and pigmented contact dermatitis. All of these disorders usually lack a clinically apparent inflammatory phase, are characterised by dermal pigmentation clinically and histologically, and have a variable protracted disease course. Recently, a proposal has been made to classify these disorders into those with and without contact sensitisation. Dermoscopy is essentially similar across the spectrum of these disorders, and is useful for diagnosis and therapeutic response monitoring. Scoring system has been validated for the same. The treatment of ADMH remains challenging, with multiple topicals, oral therapies including mycophenolate mofetil, and lasers tried. Need of the hour is randomised controlled trials to enhance the therapeutic armamentarium.

A Delphi consensus on the nomenclature and diagnosis of lichen planus pigmentosus and related entities

BACKGROUND

Although well known in clinical practice, research in lichen planus pigmentosus and related dermal pigmentary diseases is restricted due to lack of consensus on nomenclature and disease definition.

AIMS AND OBJECTIVES

Delphi exercise to define and categorise acquired dermal pigmentary diseases.

METHODS

Core areas were identified including disease definition, etiopathogenesis, risk factors, clinical features, diagnostic methods, treatment modalities and outcome measures. The Delphi exercise was conducted in three rounds.

RESULTS

Sixteen researchers representing 12 different universities across India and Australia agreed to be part of this Delphi exercise. At the end of three rounds, a consensus of >80% was reached on usage of the umbrella term 'acquired dermal macular hyperpigmentation'. It was agreed that there were minimal differences, if any, among the disorders previously defined as ashy dermatosis, erythema dyschromicum perstans, Riehl's melanosis and pigmented contact dermatitis. It was also agreed that lichen planus pigmentosus, erythema dyschromicum perstans and ashy dermatosis did not differ significantly apart from the sites of involvement, as historically described in the literature. Exposure to hair colours, sunlight and cosmetics was associated with these disorders in a significant proportion of patients. Participants agreed that both histopathology and dermatoscopy could diagnose dermal pigmentation characteristic of acquired dermal macular hyperpigmentation but could not differentiate the individual entities of ashy dermatosis, erythema dyschromicum perstans, Riehl's melanosis, lichen planus pigmentosus and pigmented contact dermatitis.

LIMITATIONS

A wider consensus involving representatives from East Asian, European and Latin American countries is required.

CONCLUSION

Acquired dermal macular hyperpigmentation could be an appropriate conglomerate terminology for acquired dermatoses characterised by idiopathic or multifactorial non-inflammatory macular dermal hyperpigmentation.

Purple-brown coalescing macules on the mandibular area of the face

This patient presented with a 1-year history of violaceous-brown, coalescing reticulated macules on his face, with no similar lesions in other body areas. Laboratory findings were normal and antinuclear antibody test was negative. Histopathological findings included lichenoid tissue reaction and prominent pigmentary incontinence.

Acquired Dermal Macular Hyperpigmentation: An Update

Acquired dermal macular hyperpigmentation (ADMH) is an umbrella term that includes disorders clinically characterized by small and large pigmented macules/patches and histopathologically showing an evidence of current or resolved interface dermatitis with pigment incontinence, without clinically significant prior inflammatory phase. The term intends to include diseases previously described in the literature as lichen planus pigmentosus, Riehl's melanosis/pigmented cosmetic dermatitis and ashy dermatosis/erythema dyschromicum perstans. The nomenclature and origin of these disorders have always been a matter of discussion. These disorders share many clinicopathological similarities, are difficult to treat and adversely affect the quality of life. Recent consensus points towards the need for a unifying term to facilitate research and therapeutic trials. This article aims to provide a comprehensive review of the recent advances in ADMH.

Psychosocial burden of lichen planus pigmentosus is similar to vitiligo, but greater than melasma: A cross-sectional study from a tertiary-care center in north India

BACKGROUND

Lichen planus pigmentosus can have a negative impact on the quality of life; however, this has not been studied in detail.

OBJECTIVES

To study the quality of life in patients with lichen planus pigmentosus and compare it with patients with vitiligo and melasma.

METHODS

This was a cross-sectional study conducted in a tertiary-care center in north India from January 2018 to May 2019. Patients ≥ 18 years of age with lichen planus pigmentosus (n = 125), vitiligo (n = 113) and melasma (n = 121) completed the Dermatology Life Quality Index (DLQI) questionnaire and answered a global question on the effect of disease on their lives. In addition, patients with vitiligo completed the Vitiligo Impact Scale (VIS)-22 questionnaire, while those with lichen planus pigmentosus and melasma filled a modified version of VIS-22.

RESULTS

The mean DLQI scores in patients with lichen planus pigmentosus, vitiligo and melasma were 10.9 ± 5.95, 9.73 ± 6.51 and 8.39 ± 5.92, respectively, the difference being statistically significant only between lichen planus pigmentosus and melasma (P < 0.001). The corresponding mean modified VIS-22/VIS-22 scores were 26.82 ± 11.89, 25.82 ± 14.03 and 18.87 ± 11.84, respectively. This difference was statistically significant between lichen planus pigmentosus and melasma, and between vitiligo and melasma (P < 0.001 for both). As compared to vitiligo, patients with lichen planus pigmentosus had a significantly greater impact on "symptoms and feelings" domain (P < 0.001) on DLQI, and on "social interactions" (P = 0.02) and "depression" (P = 0.04) domains on VIS-22. As compared to melasma, patients with lichen planus pigmentosus had significantly higher scores for "symptoms and feelings," "daily activities," "leisure" and "work and school" domains of DLQI, and all domains of VIS-22. Female gender was more associated with impairment in quality of life in patients with lichen planus pigmentosus, while lower education, marriage, younger age and increasing disease duration showed a directional trend.

LIMITATIONS

Use of DLQI and modified version of VIS-22 scales in the absence of a pigmentary disease-specific quality-of-life instrument.

CONCLUSION

Patients with lichen planus pigmentosus have a significantly impaired quality of life. The psychosocial burden of lichen planus pigmentosus is quantitatively similar to that of vitiligo, but significantly greater than melasma.

Ashy Dermatosis and Lichen Planus Pigmentosus: The Histopathological Differences

Background

Ashy dermatosis (AD) and lichen planus pigmentosus (LPP) are both acquired macular pigmentation of uncertain aetiology. Despite the controversy surrounding their entities, recent global consensus has concluded that they are 2 different diseases with distinct clinical presentations. Nevertheless, there are limited data on their histopathological comparisons.

Objective

To evaluate the differences in histopathological findings between AD and LPP.

Methods

Electronic records and photographs of patients with the diagnosis of AD or LPP from January 2008 to December 2018 were retrospectively reviewed by a dermatologist. Patients were then classified into groups with AD and LPP, based on the clinical descriptions from the recent consensus. Those with history/clinical presentations suggestive of other causes of macular pigmentation were excluded. The histopathological diagnosis of AD and LPP was then reevaluated by a blinded dermatopathologist.

Results

One hundred and twenty-four patients with acquired macular pigmentation were identified; 24 were excluded due to clinical history or photographs being inconsistent with AD or LPP. Of the remaining 100 patients, 71 had clinical findings consistent with LPP while 29 had AD. The prevalence of epidermal hyperkeratosis was significantly higher in LPP when compared to AD (33.8% vs. 0%, p < 0.001), as well as epidermal hypergranulosis (35.2% vs. 0%, p < 0.001), lichenoid dermatitis (49.3% vs. 7.1%, p < 0.001), perifollicular infiltration (47.9% vs.10.3%, p < 0.001), and perifollicular fibrosis (35.2% vs. 10.3%, p=0.01). In addition, the degree of pigmentary incontinence was more severe in LPP (21.1% vs. 3.5%, p=0.015). For AD, vacuolization of the epidermal basal cell layer was more common (96.4% vs. 77.5%, p=0.02).

Conclusions

Although most cases of AD and LPP can be diagnosed clinically, in doubtful cases, histopathological findings of lichenoid dermatitis, epidermal hyperkeratosis/hypergranulosis, and moderate to severe pigmentary incontinence can help distinguish LPP from AD.