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Abstract
[5],[6]{Figure 1}{Figure 2} In a clinicopathological study of ashy dermatosis and lichen planus pigmentosus, patients with ashy dermatosis (n = 20) were described as having symmetrical asymptomatic blue-gray macules with an erythematous border, where as patients with lichen planus pigmentosus (n = 11) had pruritic, darker macules without the active red border. While not every patient diagnosed as pigmented cosmetic dermatitis has a positive patch test, contact sensitivity to para-phenylenediamine, nickel, fragrances and other cosmetics has been reported in lichen planus pigmentosus and ashy dermatosis also. A global forum is presently working to reach a consensus on the nomenclature. [...]that time, a descriptive term such as "macular hyper-pigmentation of uncertain etiology" may be better which encompasses the clinical and histological features of these pigmentary disorders, while also emphasizing their poorly understood etiopathogenesis. Tienthavorn T, Tresukosol P, Sudtikoonaseth P. Patch testing and histopathology in Thai patients with hyperpigmentation due to erythema dyschromicum perstans, lichen planus pigmentosus, and pigmented contact dermatitis.