| Part 1:Clinical characteristics and pathological analysis of chemically induced acneObjective:To explore the clinical and histopathological features of chemically induced acne,and the expression of AhR and Cytochrome P450 1A1(CYP1A1)in skin in order to disclose clinical features and possible mechanisms of chemically induced acne.Methods:1.We investigated 155 acne cases with a history of chemical exposure,including smoking,occupational exposure,cosmetic exposure.Meanwhile,231 acne patients with no history of chemical exposure were served as controls.We assessed the severity of lesions(Pillsbury grading scale),type of lesions(inflammatory/non-inflammatory),and involved locations from the above recruited cases and controls.2.Two-millimeter punch biopsies were obtained from faces around skin lesions in 16patients,from back around skin lesions in 3 patients,and 6 healthy individuals were served as controls(4 biopsies taken from facess,2 biopsies taken from back).Histopathological and AhR and Cytochrome P450 1A1(CYP1A1)immunohistochemistry were performed to observe different characteristics as well as the expression of AhR and CYP1A1 genes in skin tissue.3.Calculate the sectional area(μm~2)of the sebaceous gland in skin tissue between cases and controls.Results:1.Chemically induced acne were mainly presented as the non-inflammatory lesion type.Smokers’acne mainly manifested as non-inflammatory lesions like comedones,cysts,depressed scars.The proportion of the non-inflammatory lesion type(67.74%)in smokers was higher than that in non-smokers(32.26%),the difference was statistically significant(P<0.018).Acne suffers with a history of occupational exposure mainly presented as comedones(36.36%),depressed scars and cyst(40.91%),facial pigmentation(31.82%);Acne cosmetica mainly presented as comedones(54.21%),papules and pustules(45.79%).2.The common histopathological features of chemically induced acne are as follows:epidermal hyperpigmentation(84.21%),epidermal hyperplasia(36.84%),atrophy or disappear of sebaceous glands(84.21%),perivascular inflammation(73.68%),collagen hyperplasia(47.37%)and so on.Occupational acne can also presented as hamartoma showing mantle-like columnar epithelial downgrowths(12.5%),squamous epithelial hyperplasia of hair follicle(12.5%),infundibular dilatation(25%),destruction of hair follicle(25%),peifolliculitis(37.5%),granulomatous inflammation(12.5%),micro thrombosis(12.5%);Smokers’acne also presented as destruction of hair follicle(60%),peifolliculitis(40%),granulomatous inflammation(20%),micro thrombosis(40%);Acne cosmetica can also presented as infundibular dilatation(50%).There were no distinguished features in controls.3.Immunohistochemical staining showed that there was no statistical difference in mean optical density of AhR expression between cases(224.61±90.7)and controls(285.33±94.23)(P=0.164),while the mean optical density(P<0.05)of CYP1A1 expression was significantly higher than that in the control group(74.05±12.14).The difference was statistically significant(P=0.036).4.Sebaceous gland size:The average sectional area of sebaceous glands in chemically induced acne(13733.96±19798.30μm~2)was significantly lower than that in the controls(274955.32±482861.06μm~2)(P=0.004).Conclusion:We found smokers’acne,occupational acne,acne cosmetica share the common characteristics in clinical and pathological presentations and all of them were dominated with non-inflammatory lesion,however,each type was different from each other.The atrophy of sebaceous gland,hair follicle hyperplasia and the increased expression of CYP1A1(typical target gene of AhR)indicated that chemical factors could cause similar clinical manifestations through activation of the AhR pathway and provides evidence for elucidating the mechanism and clinical features of chemically induced acne.Part 2:Clinical analysis of acne inversa related to chemical factorsObjective:According to the diagnostic criteria of acne inversa,there were 10 cases meet the diagnosis of acne inversa in the previous study.In order to compare the clinical and histopathological difference between acne inversa with and without a history of chemical exposure and exogenous acne,we carried out a second study.Methods:1.Retrospective analysis on clinical features and histopathological characteristics in the patients who were recruited from the first study met the criteria of acne inversa diagnosis.A total of 10 cases met the diagnosis of acne inversa.Data of11 patients with acne inversa who without a history of chemical exposure were collected in our outpatient department.2.Two-millimeter punch biopsies were obtained from the back regions around skin lesions in 2 patients,from the face regions around skin lesions in 1 patient.The histopathological characteristics of 4 cases who met acne inversa diagnosis with a history of chemical exposure were analyzed retrospectively.Results:1.In this study,the proportion of the scarring folliculitis type in acne inversa cases(80%)who are smokers or with a history of occupational exposure was higher than that of patients without a history of chemical exposure(20%).The scarring folliculitis type presented with double comedones,papules,nodules,depressed scars.Some of them were somokers(58.33%),some had a history of occupational exposure(33.33%)and some were overweight(50%),the mean BMI of which is 25.18±3.16 kg/m~2.2.The histopathological characteristics of acne inversa with a history of chemical exposure are as follows:Epidermal hyperpigmentation(100%),follicular hyperplasia(25%),sebaceous gland disappearance(75%),epidermal hyperplasia(75%),destruction of sebaceous gland destruction(75%)and so on.There was no histopathological change of epidermal hyperplasia,sebaceous gland destruction and granulomatous inflammation in patients without history of chemical exposure.3.The average sectional area of sebaceous glands in acne inversa with a history of chemical exposure(16753.61±21686.85μm~2)was lower than that in the control group(274955.32±482861.06μm~2),with no statistical difference(P=0.089).Conclusion:The clinical manifestations of acne inversa is complex,each clinical type may have different mechanisms,in this part,we found that the exogenous acne inversa mainly presented as the scarring folliculitis type,and may share the similar clinical features with“chemically induced acne”.Furthermore,we hypothesized that some of the“chemically induced acne”and acne inversa might share the same clinical manifestations and pathogenesis.Part 3:The relationship between acne and BMIObjective:To investigate the relationship between acne and obesity.Methods:We conducted a case-control study of risk factors[BMI(Body mass index),family history of related metabolic disorders,ect.]for acne in a population aged 10 to25 years attending outpatient departments.A total of consecutive 364 patients with acne were recruited,while 295 non-acne patients or healthy subjects served as controls.Results:1.The mean BMI was higher in moderate to severe acne patients(Pillsbury grading scale,grades 3 and 4)(21.86±2.83 kg/m2)than controls(20.22±2.43 kg/m2)(P<0.001).Moderate to severe acne was positively associated with overweight and obesity in people aged 18-25 years,with a more pronounced effect in women[Odds ratio(OR)14.526,95%confidence interval(CI)2.961-71.272,P<0.001]than in men(OR 3.528,95%CI 1.553-8.014,P=0.002).2.Body mass index in patients with thorax-back lesions were higher(22.30±2.57kg/m2)than patients without thorax-back lesions(20.68±2.23kg/m2)(P<0.001)and the relationship between thorax-back acne and overweight was observed(OR 4.480,95%CI 2.182-9.196,P<0.001).3.Presence of family history of metabolic disorders such as hypertension(OR 3.511,95%CI 1.977-6.233,P<0.001),diabetes(OR 2.697,95%CI 1.565-4.647,P<0.001),overweight and obesity(OR 1.844,95%CI 1.242-4.407,P=0.032)were also found to be associated with enhanced acne severity.Conclusion:Obese/overweight in women aged 18-25y with severe acne and family history of metabolic disorders could be risk factors of acne in Chinese acne patients.It is suggested that severe acne may be an early sign of metabolic diseases such as obesity. |
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