Segmental lichen planus pigmentosus: An unusual presentation

Major histocompatibility complex (MHC) gene frequency in acquired dermal macular hyperpigmentation: a case control study

BACKGROUND

Human leukocyte antigen (HLA) allele frequencies have a known association with the pathogenesis of various autoimmune diseases.

METHODS

We recruited 31 Indian patients of acquired dermal macular hyperpigmentation (ADMH) and 60 unrelated, age-and-gender-matched healthy controls. After history and clinical examination, 5 ml of blood in EDTA vials was collected. These samples were subjected to DNA extraction and the expression of HLA A, B, C, DR, DQ-A, and DQ-B was studied.

RESULTS

There was a predominance of females with a gender ratio of 23 : 8 and the most common phototype was Fitzpatrick type IV (83.9%). There was a significant association of HLA A*03:01 (OR: 5.8, CI: 1.7-17.0, P = 0.005), HLA B*07:02 (OR: 5.3, CI: 1.9-14.6, P = 0.003), HLA C*07:02 (OR: 4.3, CI: 1.8-9.6, P = 0.001), HLA DRB1*10:01 (OR: 7.6, CI: 1.7-38.00, P = 0.022), and HLA DRB1*15:02 (OR: 31.0, CI: 4.4-341.8, P < 0.001) with patients compared to controls, whereas HLA DQB*03:01 was less associated with patients compared to controls (OR: 0.2, CI: 0.0-0.6, P = 0.009).

CONCLUSION

Patients with ADMH are more likely to have the HLA A*03:01, HLA B 07*02, HLA C*07:02, HLA DRB1*10:01, HLA DRB1*15:02 and less likely to have the HLA DQB*03:01 allele. Larger cohort studies may thus be conducted studying these specific alleles.

A unilateral linear pattern of lichen planus pigmentosus

Lichen planus pigmentosus (LPP) is a rare chronic variant of lichen planus. LPP distribution tends to be symmetrical and is frequently seen on the face, neck, and trunk. Atypical clinical patterns of LPP, including segmental, zosteriform, and linear, were reported in the literature. Herein, we report a rare presentation of LPP in a 16- year-old female with a unilateral linear pattern along the Blascko lines.

A global consensus statement on ashy dermatosis, erythema dyschromicum perstans, lichen planus pigmentosus, idiopathic eruptive macular pigmentation, and Riehl's melanosis

Ashy dermatosis (AD), lichen planus pigmentosus (LPP), erythema dyschromicum perstans (EDP), and idiopathic eruptive macular pigmentation are several acquired macular hyperpigmentation disorders of uncertain etiology described in literature. Most of the published studies on these disorders are not exactly comparable, as there are no clear definitions and different regions in the world describe similar conditions under different names. A consensus on the terminology of various morphologies of acquired macular pigmentation of uncertain etiology was a long-felt need. Several meetings of pigmentary disorders experts were held to address this problem. A consensus was reached after several meetings and collation of e-mailed questionnaire responses and e-mail communications among the authors of publications on the above conditions. This was achieved by a global consensus forum on AD, LPP, and EDP, established after the 22nd International Pigment Cell Conference held in Singapore in 2014. Thirty-nine experts representing 18 countries participated in the deliberations. The main focus of the deliberations was terminology of the conditions; as such, we present here the consensus statement of the forum and briefly review the available literature on the subject. We have not attempted to discuss treatment modalities in detail.

Lichen Planus Pigmentosus: The Controversial Consensus

A pigmented variant of lichen planus (LP) was first reported from India in 1974 by Bhutani et al. who coined the term LP pigmentosus (LPP) to give a descriptive nomenclature to it. LP has a number of variants, one of which is LPP. This disease has also later been reported from the Middle East, Latin America, Korea, and Japan, especially in people with darker skin. It has an insidious onset. Initially, small, black or brown macules appear on sun-exposed areas. They later merge to form large hyperpigmented patches. The disease principally affects the sun-exposed areas of the body such as the face, trunk, and upper extremities. The oral mucosa may rarely be involved. However, the palms, soles, and nails are not affected. Histologically, the epidermis is atrophic along with vacuolar degeneration of basal cell layer. The dermis exhibits incontinence of pigment with scattered melanophages and a sparse follicular or perivascular infiltrate. There is a considerable similarity in histopathological findings between LPP and erythema dyschromicum perstans. However, there are immunologic and clinical differences between the two. These observations have led to a controversy regarding the identity of the two entities. While some dermatologists consider them to be the same, others have opined that the two should be considered as distinctly different diseases. A number of associations such as hepatitis C virus infection, frontal fibrosing alopecia, acrokeratosis of Bazex and nephrotic syndrome have been reported with LPP. A rare variant, LPP inversus, with similar clinical and histopathological findings was reported in 2001. As opposed to LPP, this variant occurs in covered intertriginous locations such as groins and axillae and mostly affects white-skinned persons.