Temporal changes in sebum excretion and propionibacterial colonization in preadolescent children with and without acne.
ABSTRACT It is generally accepted that the onset of sebum secretion occurs before puberty in boys and girls as a result of increasing androgen output during the adrenarche. Propionibacteria are part of the commensal skin flora and, in adults, are found in highest numbers in sebum-rich areas of skin such as the face and upper trunk. Previous studies investigating the association between sebum output and propionibacterial population densities have been cross-sectional and have been carried out mainly in adults.
The purpose of this study was to examine the association between the onset of sebum secretion and expansion of the propionibacterial flora in a population of early adolescent children aged between 5.5 and 12 years, and to evaluate the temporal relation between the two factors longitudinally. In addition, the study aimed to evaluate the change with age in sebaceous gland activity and propionibacterial colonization on the skin and in the nares between children who developed acne and those who did not.
Biannual examinations of volunteers included age, pubertal (Tanner) stage, weight and height, lesion counting on the face, propionibacterial colonization on the skin surface and in the nares and sebum secretion. A longitudinal analysis based on all observations of each subject throughout the study was applied to examine the change of sebaceous gland activity and propionibacterial colonization with age and pubertal stage. A generalized estimating equation was used with a 0.05 level of significance.
The commencement of sebum production was asynchronous, with only a small number of follicles initially starting to secrete sebum onto the skin surface. The number of secreting follicles and the area of sebum increased with age and pubertal stage (P < 0.0001, P < 0.05, respectively). Numbers of propionibacteria on the skin tended to increase after the age of 9 years, but not significantly so. In contrast, numbers of propionibacteria in the nares increased significantly with age (P < 0.0001) but not with pubertal maturation. Children who developed acne had higher sebum output and propionibacterial densities with increasing age than children who did not develop acne. This effect was significant for the increase of total sebum area with age in pubertal children (P = 0.0023), the increase in number of secreting follicles with age (P = 0.020) in prepubertal children, and the increase in propionibacteria densities in the nares with age (P = 0.0005) in pubertal children. Sebaceous gland activity and propionibacterial numbers on the skin surface remained unchanged with increasing age in children who did not develop acne. Propionibacterial population densities in the nares increased with age regardless of the development of acne.
Onset of sebum secretion and consequently expansion of the propionibacterial skin flora occur earlier in children who develop acne than in children of the same age and pubertal status who do not develop acne. These observations suggest that postponing the onset of sebum production or the expansion of the propionibacterial skin flora until after puberty may represent ways of preventing the disease or minimizing its severity. Determinants of propionibacterial colonization on the skin and in the nares may be different.
Article: Treatment of Acne in Children.[Show abstract] [Hide abstract]
ABSTRACT: Acne is a common skin condition in adolescents. It is not uncommon in childhood and it persists into adulthood. A broad range of acne treatments are available and have been shown to be safe and effective in adolescents and adults. However, there is limited literature regarding acne treatment in childhood and its available therapeutic options. It seems reasonable to extrapolate findings of the various studies reported on treatment of acne in the adolescent and adult age group, with the exclusion of the use of tetracycline derivatives. As clinicians, we must be more familiar with the clinical presentation of acne and available treatment options in our younger patients. Early recognition of acne with prompt and appropriate initiation of therapy in childhood will help prevent severe scarring in children.American Journal of Clinical Dermatology 01/2014; · 2.52 Impact Factor
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ABSTRACT: Acne vulgaris is the most frequently diagnosed dermatosis in patients between 11 and 30. It is believed that it affects about 80% of persons in this age group or even, taking into account lesions of low intensity, 100% of young people. The etiopathogenesis of acne is multifactorial. In all patients with acne the following symptoms occur: excessive sebum production, excessive keratosis of excretory ducts and openings of sebaceous glands, development of bacterial flora and release of inflammatory mediators in the skin. Development of molecular biology, genetics and immunology contributed to a significant progress in studies on the pathogenesis of acne. This article is protected by copyright. All rights reserved.International journal of cosmetic science 02/2014;
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ABSTRACT: Neisseria meningitidis is an important human pathogen that is capable of killing within hours of infection. Its normal habitat is the nasopharynx of adult humans. Here we identify a genomic island (the prp gene cluster) in N. meningitidis that enables this species to utilize propionic acid as a supplementary carbon source during growth, particularly under nutrient poor growth conditions. The prp gene cluster encodes enzymes for a methylcitrate cycle. Novel aspects of the methylcitrate cycle in N. meningitidis include a propionate kinase which was purified and characterised, and a putative propionate transporter. This genomic island is absent from the close relative of N. meningitidis, the commensal N. lactamica, which chiefly colonises infants not adults. We reason that the possession of the prp genes provides a metabolic advantage to N. meningitidis in the adult oral cavity, which is rich in propionic acid-generating bacteria. Data from classical microbiological and sequence-based microbiome studies provide several lines of supporting evidence that Neisseria meningitidis colonisation is correlated with propionic acid generating bacteria, with a strong correlation between prp-containing Neisseria and propionic acid generating bacteria from the genus Porphyromonas, and that this may explain adolescent / adult colonisation by N. meningitidis.Molecular Microbiology 06/2014; · 4.96 Impact Factor