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PubMed1989

Acne is not associated with abnormal plasma androgens.

Plasma dehydroepiandrosterone sulphate, androstenedione, testosterone (T), dihydrotestosterone (DHT), and sex hormone binding globulin (SHBG) have been measured in 64 females and 26 males aged less than 25 years and with acne vulgaris. Oestradiol was measured in the males. Free T and free DHT were calculated. Acne was graded on three sites and the sebum excretion rate (SER) was measured in most patients. With the possible exception of free DHT, none of the plasma steroids or SHBG correlated with acne severity or with SER. Free DHT in the females showed a possible, but weak, correlation with total acne (r = 0.25, P = 0.07), but comparison with male data showed that this was not causative. The role of androgens in acne is permissive and plasma androgen measurements usually have no place in its management.

Acne Vulgaris↗
PubMed2003

Prevalence of pityriasis versicolor in young Italian sailors.

BACKGROUND: Pityriasis versicolor is a superficial fungal disease with a world-wide distribution, but there are few available studies on its prevalence in the general population. OBJECTIVES: To assess the prevalence of pityriasis versicolor in a representative sample of young Italian sailors, evaluating the influence of habits and risk factors in the affected individuals. METHODS: Young cadets (n = 1024: 975 men and 49 women, mean age 22 years) of the Italian Navy Petty Officers' School in Taranto were consecutively examined by the same observer. The diagnosis of pityriasis versicolor was based on clinical picture and/or Wood's lamp examination. All the subjects filled in a questionnaire about sport practice, swimming pool attendance, marching, presence of hyperhidrosis and a positive clinical history of pityriasis versicolor in the past. The affected individuals were also asked if they were aware of their skin lesions. Differences between answers of affected and unaffected subjects were tested by Fisher's exact P-value test, and odds ratios were calculated. RESULTS: Pityriasis versicolor was diagnosed in 22 subjects (2.1%), all men, of whom 15 (68%) were not aware of their condition. No statistical association was found between active pityriasis versicolor and sport practice, swimming pool attendance, marching or presence of hyperhidrosis. A significant association [odds ratio 8.7 (95% confidence interval 3.3-21.5); Fisher's exact P-value test P < 0.01] was documented between active pityriasis versicolor and a previous clinical history of pityriasis versicolor. CONCLUSIONS: The prevalence of pityriasis versicolor in this sample of young Italian sailors was not high, in agreement with the available surveys performed in the general population in temperate climates. Many affected subjects were not aware of their condition. The only important factor associated with pityriasis versicolor was a previous history of pityriasis versicolor. This observation could confirm the hypothesis that constitutional factors, e.g. seborrhoea and chemical constitution of sebum, may play a crucial role in temperate climates, leading to relapsing forms of this superficial mycosis.

Adolescent↗
PubMed2006

Investigation of the mechanism of action of nonablative pulsed-dye laser therapy in photorejuvenation and inflammatory acne vulgaris.

BACKGROUND: Nonablative lasers are widely used for treatment of wrinkles, atrophic scars and acne. These lasers stimulate dermal remodelling and collagen production, but the early molecular stimulus for this is unknown. The mechanism of nonablative lasers in inflammatory acne is variously suggested to be damage either to sebaceous glands or to Propionibacterium acnes. Their effects on cytokine production are unknown. OBJECTIVES: To assess the in vivo effects of a short pulse duration nonablative pulsed-dye laser (NA-PDL) previously used for photorejuvenation and treatment of acne, on cytokine production, P. acnes colonization density and sebum excretion rate (SER). METHODS: We examined the effect of NA-PDL (NliteV; Chromogenex Light Technologies, Llanelli, U.K.) on P. acnes colonization before and after laser therapy using a scrub-wash technique and culture at 0 and 24 h (n = 15), on SER using absorptive tape at 0, 2, 4, 8 and 12 weeks (n = 19) and on cytokine mRNA using reverse transcription-polymerase chain reaction from skin biopsies at 0, 3 and 24 h (n = 8). Results NA-PDL had no effect on P. acnes or SER. Transforming growth factor (TGF)-beta1 mRNA increased fivefold after 24 h and 15-fold in two subjects (P = 0.012). CONCLUSIONS: TGF-beta is known to be a potent stimulus for neocollagenesis and a pivotal immunosuppressive cytokine which promotes inflammation resolution. Its upregulation by NA-PDL provides a possible unifying molecular mechanism linking stimulation of dermal remodelling in photorejuvenation with inhibition of inflammation in acne. Damage to P. acnes or sebaceous glands cannot explain the effect of this device in acne.

Acne Vulgaris↗
PubMed1994

Effects of castration and testosterone on Fel dI production by sebaceous glands of male cats: II--Morphometric assessment.

A morphometric study of cat sebaceous glands was performed to evaluate the effects of castration and testosterone treatments. Skin biopsies were taken in six cats before castration, after castration and after the testosterone injections administered after castration (total number of biopsies: 18). Ninety 8 microns thick sections of each biopsy were assessed for image analysis processing (SAMBA 2005, ALCATEL TITN). The variations in glands and cells size were evaluated on digitized microscopic images by morphometric parameters included in the SAMBA software package. An original software was developed for the analysis of the spacial gland structure. The best morphometric parameters were selected in a first step of the study, and included the nuclear surface (NS), the cell surface (CS) and the nuclear/cellular surface ratio (N/C). These three parameters were then compared in each group of samples for the six cats. It was shown that after castration the N/C (21%) significantly increased compared with prior to castration (12.6%). This 59.8% increase was mainly due to cell cytoplasm shrinking reflecting a decrease of the cell activity. The testosterone administered after castration produced a reverse effect with a N/C ratio back to normal (11.4%) and a significant cell cytoplasm and gland enlargement as shown by the three dimension constructions. This morphometric data correlated with the measurement of sebum and Fel dI productions. The negative effects of castration and the positive effects of testosterone on the sebaceous cells and glands volume favour the hypothesis that cat sebaceous cells are subject to hormonal control this is also likely to apply to the Fel dI production.

Allergens↗
PubMed1983

Indirect evidence that the action of cyproterone acetate on the skin is due to a metabolite.

Cyproterone acetate, applied as 1% solution in ethanol or isopropyl myristate, did not decrease the sebum excretion rate (SER) when applied to forehead skin of patients with acne, although SER is decreased when the drug is given systemically. The probable explanation is that cyproterone acetate owes its local action to a metabolite formed systemically. The present study shows this is unlikely to be the 17 beta-hydroxy cyproterone acetate.

Acne Vulgaris↗
PubMedDate not supplied

Assessment of etiologic agents in acne pathogenesis.

Acne is a chronic inflammatory disease of the pilosebaceous units. Traditional etiologic factors include increased sebum production, ductal hyperkeratosis, abnormality of the microbial flora within the pilosebaceous unit, and mediators of inflammation. Recent developments do not refute these familial elements, but rather refine particular aspects. Interleukin-1a influences hypercornification of the infundibulum as well as the inflammatory response by inducing the production of vascular endothelial growth factor in dermal papilla cells and follicular keratinocytes of the pilosebaceous unit. New retinoids have been developed based on controlling cellular proliferation and differentiation in the pilosebaceous unit by their action on nuclear receptors of cells. Dermal inflammation is not due to presence of bacteria, but from biologically active mediators produced by Propionibacterium acnes. The environment within the pilosebaceous unit is probably more important than the absolute number of P. acnes organisms. Indeed, the major role of the sebaceous gland appears to be supplying P. acnes needed nutrients. Moreover, the microbiologic principle of biofilms appears to be applicable to P. acnes in acne.

Acne Vulgaris↗
PubMed2003

Proopiomelanocortin peptides and sebogenesis.

Previous animal studies have demonstrated that alpha-melanocyte-stimulating hormone (alpha-MSH) is a sebotropic hormone in rats and that targeted disruption of melanocortin 5 receptor (MC5-R) can down-regulate sebum output in mice. To study the role of proopiomelanocortin (POMC) peptides in the regulation of human sebaceous lipid production and sebocyte differentiation, we established a primary human sebocyte culture system. Sebocytes were derived from normal human facial skin. Differentiation of sebocytes, induced by POMC-derived peptides such as MSH, adrenocorticotropic hormone (ACTH), or bovine pituitary extract (BPE), resulted in the appearance of prominent cytoplasmic lipid droplets. Partial induction of sebocyte differentiation also was observed in serum-depleted cultures, but there was very limited spontaneous differentiation in serum-containing medium. Analysis by high-performance thin-layer chromatography (HPTLC) of (14)C-acetate-labeled lipids showed a dose-dependent increase in synthesis of sebaceous-specific lipid (i.e., squalene) induced by NDP alpha-MSH. Molecular studies using RT-PCR showed a low level of human MC5-R expression under serum-free condition but a substantial increase after treatment with NDP alpha-MSH or BPE. In contrast, MC1-R expression remained the same, independent of treatment. Our data indicate that expression of MC5-R correlates with sebocyte differentiation and suggest a regulatory role for MC5-R in human sebaceous lipid production.

Animals↗
PubMed1978

Regional variations of cutaneous propionibacteria.

Propionibacterium acnes, P. avidum, and P. granulosum were quantitatively measured in 50 young adults. The scalp, forehead, external auditory canal, alae nasi, anterior nares, groin, rectum, and antecubital and popliteal fossa were sampled. These represent various cutaneous microenvironments, differing in moisture, density of sweat, sebaceous glands, and extent of anaerobiosis. These studies show that the propionibacteria are ubiquitous on the skin, with P. acnes predominant in both prevalence and population, especially in areas rich in sebum. P. granulosum recovery paralled that of P. acnes, but the density was significantly lower. P. avidum was found mainly in moist areas and the retum, suggesting an intestinal reservoir.

Adolescent↗
PubMed1979

Characteristic gamma-lactone odor production of the genus Pityrosporum.

Mass spectrometric-gas chromatographic analysis of culture headspaces revealed that members of the genous Pityrosporum produce volatile gamma-lactones during growth on lipid-containing media. Representative members of other yeast genera found on humans failed to produce these compounds. Addition of lecithin, oleic acids, triolein, or human sebum to the culture media stimulated gamma-lactone production by Pityrosporum species. All yeasts tested produced isopentanol and phenylethanol. Production of gamma-lactones may serve as a valuable characteristic in the identification of organisms of the genus Pityrosporum.

Culture Media↗
PubMed1980

Regional variations in density of cutaneous propionibacteria: correlation of Propionibacterium acnes populations with sebaceous secretion.

Cutaneous Propionibacterium acnes populations were quantitatively measured in 33 young adults and compared with the rate and composition of sebum secretion in nine skin regions. Bacteriological and lipid analyses were performed on the forehead, cheek, anterior chest, abdomen, lower back, volar forearm, upper inner arm, thigh, and calf. P. acnes populations in these sites correlated significantly with the total amount of lipid produced (r = 0.77) as well as with di- and triglycerides (r = 0.68), squalene and wax esters (r = 0.72), cholesterol and cholesterol esters (r = 0.67), and free fatty acids (r = 0.67).

Adolescent↗
PubMed1976

Thyroid disease and sebaceous function.

Sebum excretion rates (SER) were measured before and after treatment in patients with hypothyroidism and thyrotoxicosis. The mean SER in the former was significantly less than that in normal controls but there was no correlation between SER and the severity of the disease as indicated by serum thyroid-stimulating hormone levels. After treatment with L-thyroxine the SER increased but remained subnormal. By contrast the SER was not increased in patients with thyrotoxicosis and it was unaffected by treatment. The human sebaceous gland seems to respond to thyroid hormone mainly in the hypothyroid range.

Adolescent↗
PubMed1983

Seborrhoea is not a feature of seborrhoeic dermatitis.

The sebum excretion rate from forehead skin was measured in 44 patients with classic seborrhoeic dermatitis and 200 control subjects. The mean excretion rate was normal in the 29 men with seborrhoeic dermatitis and significantly reduced in the 15 women with the disease. This study showed that seborrhoeic dermatitis is not usually associated with seborrhoea, and therefore "dermatitis of the sebaceous areas" may be a more accurate term.

Adolescent↗
PubMed2005

Gender-related differences in the physiology of the stratum corneum.

BACKGROUND: Only few studies on gender-related differences in skin physiology have been performed--and they provided conflicting results. OBJECTIVE: In the present study, the effect of gender on the physiology of the stratum corneum was studied. METHODS: The physiological parameters transepidermal water loss, pH value, hydration and sebum content were determined on the flexor forearms of 6 female and 6 male volunteers. In addition, stratum corneum samples, removed by tape stripping, were studied for amount, spectroscopic properties, protein content, and mass. RESULTS: The skin of women was characterized by a significantly higher pH value (5.6 +/- 0.4) than that of men (4.3 +/- 0.4, p < 0.05). Protein absorption was the only other parameter significantly dependent on gender (p < 0.05). Both effects might be caused by differences in human biology, such as hormonal status. CONCLUSION: Therefore, the gender of the volunteers should be considered in dermatologic studies.

Adult↗
PubMed1997

Tinea capitis in adults: misdiagnosis or reappearance?

BACKGROUND: According to the literature, tinea capitis in adults is supposed to be rare; we have recently observed a significant increase in cases. METHODS: Epidemiological, clinical and mycological features were studied in all adult tinea capitis diagnosed over 1 year in our department. RESULTS: Eight cases were observed: 75% of them were women, 50% never traveled and 62.5% had an underlying immunosuppressive disease. Scalp scaling and alopecia were the most frequent clinical features. A zoophilic dermatophyte was recovered in 50% of cases. CONCLUSION: These cases represent 11% of all tinea capitis observed in the same period of time (higher than the 3-5% observed in the literature). Secretion of sebum and colonization by Pityrosporon orbiculare are supported to protect the scalp against dermatophytic invasion after puberty, but an immune defect may also facilitate hair invasion. The erroneous notion of the disease being uncommon and the frequent atypical clinical presentation require a high degree of clinical suspicion.

Adult↗
PubMed1987

Seborrhoea in acne-prone and acne-free patients.

We have studied the relationship between seborrhoea and acne by using the Lipometre and Sebutape films. Seborrhoea is more intense in acne-prone than in acne-free patients. For a given overall amount of sebum excreted, the individual activity of sebaceous follicles differs in the two groups of individuals tested. Seborrhoea in acne-prone patients is due to the presence of some highly active follicles that are almost never encountered in acne-free patients.

Acne Vulgaris↗
PubMed1981

Failure of benzoyl peroxide to decrease sebaceous gland secretion in acne.

10 male patients with inflammatory facial acne were treated for 6 weeks with a 10% benzoyl peroxide gel (PanOxyl-10) applied to the forehead. There was no significant mean change in sebaceous gland secretion after 4, 5, and 6 weeks of treatment. These findings are at variance with a previously published study which showed that 5% benzoyl peroxide gel inhibited sebaceous gland secretion. Conflicting results from the two studies may be due to differences in patient populations or, more likely, in technical factors, such as the methods used for sebum production, collection, and analysis.

Acne Vulgaris↗