ABSTRACT
OBJECTIVE: Erythema dyschromicum perstans (EDP) can be difficult to diagnose and treat; therefore, we reviewed the literature to assess whether histology can be used to differentiate lichen planus pigmentosus (LPP) from EDP and determine which treatments are the most effective for EDP. We also present a case of a patient who was treated successfully with narrow-band ultraviolet B (NB-UVB). METHODS: A systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was conducted up to July 2017 using four databases. RESULTS: Histologic analyses from the literature reveal a significant percentage of melanophages, lymphocytic infiltrates, and basal vacuolar degeneration in EDP, and a significant histologic overlap with LPP. The review of the literature on treatment outcomes showed that NB-UVB and tacrolimus were effective with minimal side effects. Clofazimine was effective, but demonstrated significant-to-intolerable side effects. Griseofulvin, isotretinoin, and dapsone provided unsatisfactory results as lesions recurred after discontinuation. Lasers were largely ineffective and may cause postinflammatory hyperpigmentation and fibrosis. CONCLUSION: A diagnosis of EDP should not be based on histologic findings alone. Clinical history, morphology, and distribution should be used to differentiate EDP and LPP. NB-UVB and tacrolimus are promising treatments for EDP with minimal side effects. This is the first report to our knowledge of sustained resolution of EDP after treatment with NB-UVB at long-term follow-up of 4 years. Larger studies are needed to confirm these findings.
ABSTRACT
Filaggrins are an important class of intermediate filament-associated proteins that interact with keratin intermediate filaments of terminally differentiating mammalian epidermis. They show wide species variations and their aberrant expression has been implicated in a number of keratinizing disorders. We have isolated a cDNA clone encoding human filaggrin and used this to demonstrate that the human gene encodes a polyprotein precursor containing numerous tandem filaggrin repeats. This structure is similar to that of mouse; however, the human filaggrin repeat is much longer (972 base pairs; 324 amino acids) and shows little sequence homology to the mouse protein. Also, data presented here reveal that the human filaggrin repeats show considerable sequence variations; such polymorphism is not found in the mouse. Furthermore, chromosomal mapping data revealed that the human gene is located at 1q21, indicating that the polymorphism is confined to a single locus. By peptide mapping, we define a short linker sequence within the human filaggrin repeat that is excised by proteolysis to yield functional molecules. Finally, we show by in situ hybridization that human filaggrin precursor gene expression is tightly regulated at the transcriptional level in terminally differentiating epidermis and that this represents a useful system in which to study intermediate filament-intermediate filament-associated protein interactions as well as disorders of keratinization.
