Prurigo Pigmentosa:four Cases And Literature Review

Objective The purpose of this study was to collect clinical data,histopathological and other auxiliary examination results,treatment and outcome of Prurigo Pigmentosa(PP)in our hospital and in patients reported at home and abroad.We will analyze and study these data to improve the understanding of the disease,so as to reduce the misdiagnosis rate,which is conducive to the correct diagnosis and treatment of the disease by clinicians.Methods We described four cases of PP diagnosed and treated in the dermatology department of Affiliated Hospital of Nantong University from 2017 to 2019.The general condition,medical history,clinical presentation,histopathological examination,diagnosis,treatment and outcome were recorded in detail.By retrieving domestic and foreign literature reports on pigmented pruritus from CNKI,Wanfang medical data center,Pubmed and other databases,we collected the cases of PP from 2007 to 2019 with relatively complete data for analysis and comparison.Meanwhile,we reviewed previously published literature on the epidemiology,etiology,diagnosis,differential diagnosis,treatment and prognosis of PP.Results The male to female ratio of PP in four cases in our hospital was 1:1,with an average age of(31.0±11.3)years,and the course of disease ranged from 1 month to 6 years.Among them,3patients were misdiagnosed as ‘Eczema’ before the diagnosis of PP,and1 patient was misdiagnosed as ‘Eczema’ and ‘Drug Eruption’.Before diagnosis,these patients were treated with antihistamines or glucocorticoids with poor results.Three of the patients presented with erythema and papules,and reticular pigment spots were observed after the rash subsided.Only scattered papules and pigmentation were observed in 1 patient.Fungal examination of skin lesions in all 4 patients was negative,histopathological examination showed non-specificity,and lymphocyte infiltration of different degrees was observed in the dermis,among which 3 patients had epidermal edema.After the diagnosis of PP,all patients were treated with minocycline at a dose of 100 ～ 200mg/d.The rash resolved significantly after 1 week of treatment,with only reticular pigmentation spot remaining after 4 weeks of consolidation,and no new rash.Reviewing relevant literature,we collected a total of 42 cases.There were 36 cases in Asia and 6 cases in other countries or regions.The male to female ratio was 1:2.5(12/30),the mean age was(24.2±9.5)years(except 3 cases whose specific age was unclear),and the course of disease ranged from 1 week to 40 years.69%(29/42)were diagnosed with other diseases,while 31%(13/42)were diagnosed directly with PP.Most diagnosis is ‘Eczema’,‘Atopic Dermatitis’,‘Drug Eruption’,‘Confluent and Reticulate Papillomatosis’,‘Pityriasis Versicolor’.The treatment regimen was minocycline or doxycycline,100 to 200mg/d,with improvement beginning at an average of 2 to 3 weeks.Conclusions Due to the lack of early understanding of the disease,PP is prone to misdiagnosis and missed diagnosis.It shows that PP is not an extremely rare skin disease,because in recent years,domestic and foreign reports have increased.The diagnosis of PP mainly depends on clinical manifestations,and histopathological examination can be used as the basis of auxiliary diagnosis.Antihistamines and hormones have no effect on PP.Tetracyclines,especially minocycline and doxycycline,are the preferred drugs.Dapsone and isotretinoin have been shown to be effective,but do not reduce the recurrence rate.We should raise the awareness of the disease and the rate of diagnosis.