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PubMed1978

[Toxic dermatitis and pseudo-contact allergy].

A contact dermatitis is more often due to skin irritation than to allergic reactions. About 80% of occupational dermatoses are explicable as toxic reactions of the skin, 20% as allergic reactions. Frequency and severity of the diseases depends on the nature and concentration of a substance as well as from the duration of its action on the skin. Defense mechanisms against chemicals are influenced by sebum content, humidity and the integrity of the horny layer. From a practical standpoint it is important to differentiate toxic from allergic reactions in a patch-test. It seems that allergic reactions are diagnosed too often. The determination of the critical non-toxic concentration requires the evaluation of a sufficient number of patients. The differentiation of irritation and allergy is tendered more difficult by individual factors. The therapy of toxic and allergic contact dermatitis is discussed.

Allergens↗
PubMed1985

Ventral scent marking in Meriones unguiculatus may contribute to thermoregulation.

Three experiments were conducted with adult male Meriones unguiculatus in an attempt to demonstrate that ventral scent marking can act to transfer body heat to the object marked. Experiment 1 showed that surgical removal of the ventral gland pad reduced the amount of heat transferred by 50%, even though intact and glandless animals did not differ in the average frequency of scent marking. Experiment 2 demonstrated that the difference in heat transfer due to the presence or absence of the scent pad was not due to differential pressure applied to the substrate during marking. Experiment 3 showed that the pattern of ventral hair spread that occurs as an animal moves over an object is different between intact and glandless animals but that this difference does not account for the difference in heat transfer. It is suggested that heat transfer to the environment with ventral scent marking may increase thermoregulatory competence and also may function to volatilize sebum used in chemocommunication.

Animal Communication↗
PubMed1985

Structure of the epidermis of Australian Merino sheep over a 12-month period.

Light-microscopic examination of frozen sections of skin taken from the dorsal thoraco-lumbar region of Australian Merino sheep in winter revealed that the thickness of the epidermis plus a sudanophilic layer was 24.9 micron in the interfollicular region. The uncornified epidermis (10.9 micron) was separated from the sudanophilic layer (14.0 micron) by a thin stratum corneum. It was concluded that the bulk of the sudanophilic layer was emulsified sebum in which was embedded a disorganized collection of desquamated cornified cells. Although large variances were observed in the thickness of the uncornified epidermis and of the sudanophilic layers between sheep and both within the between blocks of tissue obtained from individual sheep, there were no strong seasonal effects on either epidermal structure or layer thickness over a 12-month period. These results suggest that the Australian Merino differs from Finnish Landrace X Dorset Horn ewes, which are reported to possess, at least in winter, a thicker uncornified epidermis and a thicker stratum corneum that could be divided into two zones and was uniformly permeated by lipid.

Acclimatization↗
PubMedDate not supplied

Isotretinoin: new therapy for severe acne.

The chemistry, pharmacology, pharmacokinetics, clinical use, adverse effects, dosage and administration, and FDA-approved indications of isotretinoin, a new agent used for treating acne, are reviewed. Isotretinoin is a synthetic retinoid compound with pharmacologic actions similar to those of other retinoids. Isotretinoin's effects on nodulocystic acne lesions apparently result from its reduction of the size of sebaceous glands, inhibition of sebum production, and inhibition of follicular keratinization. Isotretinoin is administered orally; peak serum drug concentrations occur approximately three hours after ingestion. The drug is widely distributed throughout body tissues and metabolized by the liver by oxidation and glucuronidation; both parent drug and metabolites are excreted in the urine and feces. Clinical trials of isotretinoin have shown the drug to be effective in treating cystic or conglobate acne that is unresponsive to therapy with oral or topical antibiotics, topical tretinoin, or topical benzoyl peroxide. Isotretinoin is unique in that acne remission continues after discontinuance of therapy. The most frequent adverse effects involve mucocutaneous tissues and include cheilitis, xerosis, xerostomia, dry nose, epistaxis, and pruritus. Other adverse effects--including some serious ones--have been found rarely in humans or animals receiving isotretinoin. The usual oral dosage of isotretinoin for patients with cystic acne is 1-2 mg/kg/day in two divided doses; administration should continue for 15-20 weeks. Isotretinoin is currently more expensive than other acne treatments. Isotretinoin is an effective agent for treating cystic acne; pending accumulation of further data, its use should be limited to patients with severe conditions that do not respond to older therapies because of isotretinoin's cost and sometimes serious adverse effects.

Acne Vulgaris↗
PubMed1983

Quantitative variations in distribution of Pityrosporum orbiculare on clinically normal skin.

The lipophilic yeast Pityrosporum orbiculare has been cultured quantitatively, in 10 volunteers, from clinically normal skin on the chest, back, upper arm, lower leg, and dorsal aspect of the hand. The highest count was on the back (mean 333/cm2) and chest (mean 327/cm2). This was statistically significant higher than on the upper arm (mean 21/cm2), lower leg (mean 13/cm2), and dorsal aspect of the hand (mean 2/cm2). The variations in number of P. orbiculare parallels both regional variations in sebum excretion and the distribution of tinea versicolor lesions.

Adolescent↗
PubMed1982

[Clinico-experimental studies on the effect of benzoylperoxide].

Clinical and experimental investigations to characterize therapeutic effects of topically applied benzoyl peroxide (5 and 10% in alcohol-free gel formulation) were performed with: quantitative determination of bacteria in the follicular filaments with the cyanoacrylate technique (P. acnes and micrococcaceae); agar diffusion method for bacteriostatic effects; semi-quantitative determination of skin surface lipids (ground glass method); lipid solvent and thin-layer chromatography (free fatty acids vs. triglycerides); scanning electron microscopy of the skin surface; exfoliative cytology with corneocyte counts in a Fuchs-Rosenthal chamber (corneocytes/cm2 skin surface); determination of corneocyte surface are in micrometer2; and a clinical trial concerning efficacy and tolerance of the gel formulation. Topically applied benzoyl peroxide acts antibacterially and keratolytically, has anti-lipolytic activity, reduces bacteria in the follicular infundibula, but does not inhibit sebum production as measured by skin surface lipids. Benzoyl peroxide stimulates the epidermopoiesis with reduction of corneocytes/cm2 from 87,400 +/- 29,000 to 36,000 +/- 19,000 (day 15 of treatment) with diminution in size of corneocytes from 1,018 micrometers2 +/- 74 to 865 micrometers2 +/- 65 vs. 832 micrometers2 +/- 85 (5% vs. 10% benzoyl peroxide). Alcohol-free gels of benzoyl peroxide are better tolerated by acne patients than those containing alcohol, in particular when combined with topical tretinoin (vitamin A acid) treatment.

Acne Vulgaris↗
PubMed1983

[Oral treatment of acne conglobata using 13-cis-retinoic acid. Results of the German multicentric study following 24 weeks of treatment].

Results of the isotretinoin (13-cis-retinoic acid, Ro 4-3780) German Cooperative Study Group, with 198 acne conglobata patients being treated in 19 departments are reported. For the first 12 weeks (phase I) there was an open assignment to 0.2, 0.5 or 1.0 mg/kilogram bodyweight (kg bw). This was followed by further 12 weeks (phase II). If there was at least a two-third improvement of lesions, the 0.2 mg/kg bw was continued, and the 0.5 mg/kg bw dose lowered to 0.2 mg/kg bw. If there was no such improvement, the dose was elevated to 0.5 and 1.0 mg/kg bw respectively. The initial high dose group of 1.0 mg/kg bw was divided after twelve weeks into 0.2 mg/kg bw maintenance therapy, or no therapy at all. Non-inflammatory and inflammatory acne lesions from the entire body were counted. Seborrhea was graded on a four scale (0 to 3+). Subjective side effects were registered. Laboratory data included hematological profile with differential counts, creatinin, SGOT, SGPT, alkaline phosphatase, total bilirubin, serum cholesterol and serum triglycerides, and urine analysis. For statistical analysis 171 patients were available, 27 dropped out of the study, mostly for reasons unrelated to the drug. At least 75 per cent improvement was seen, in the 0.2 mg/kg bw group in 73.7 and 59.5 per cent respectively; in the 0.5 mg/kg bw group in 72.5 and 61.2 per cent respectively; and in the 1.0 mg/kg bw group in 85.4 and 92 per cent respectively (phase I t12 and phase II t24 values, respectively). Sebum suppression was dose-related. Subjective side effects were fairly well dose-related, particularly those of skin and mucous membranes. Myalgia was rare. There was a dose-related elevation of triglycerides and cholesterol, but not significant for the means of each group. Single patients did show significant elevation of blood lipids. All other laboratory parameters did not change significantly. Isotretinoin is presently the most effective drug to control severe forms of acne, leading to long lasting remissions.

Acne Vulgaris↗
PubMedDate not supplied

Evaluation of ketoconazole.

The pharmacology, microbiology, pharmacokinetics, clinical use, adverse effects, dosage and administration, and drug interactions of ketoconazole are reviewed. Ketoconazole, a new orally active antifungal agent, is an imidazole derivative structurally related to miconazole and clotrimazole. It impairs the synthesis of ergosterol (the main sterol in fungal cell membranes) in susceptible organisms, including yeast (Candida and Cryptococcus spp.), fungi, and dermatophytes. Ketoconazole is absorbed from the gastrointestinal tract; it is better absorbed from acidic aqueous solutions, so drugs that alter the pH of the stomach affect ketoconazole absorption. Therapeutic plasma concentrations are maintained for several hours following ketoconazole administration. Ketoconazole distributes readily into blood, urine, saliva, joint fluid, sebum, and cerumen; recent data indicate it may penetrate into cerebrospinal fluid as well. Elimination is biphasic, with a half-life of two hours during the first 10 hours following a dose, and a half-life of eight hours thereafter. Ketoconazole is metabolized by the hepatic microsomal oxidation system; metabolites are excreted renally. Ketoconazole is effective in treatment of several local and systemic fungal infections. It is approved by FDA for treating candidiasis, chronic mucocutaneous candidiasis, oral thrush, candiduria, coccidioidomycosis, histoplasmosis, chromomycosis, and paracoccidioidomycosis. Ketoconazole has also shown promise in other conditions not yet approved by FDA, including dermatophytosis, pityriasis versicolor, and vaginal candidosis. Controlled, comparative, double-blind trials of ketoconazole versus older agents are generally unavailable. Nausea and vomiting are the most common adverse effects encountered with ketoconazole. Transient elevations in serum liver enzymes have been noted occasionally. Initial daily ketoconazole dosage is 200 mg taken with a meal; 400 mg daily has been used for some conditions. Ketoconazole is a promising new drug, especially when one considers other available antifungal agents. However, large-scale comparative studies are not yet available; a more definitive evaluation of efficacy and safety, especially when the drug is used for long periods of time, must await more widespread use of ketoconazole.

Fungi↗
PubMed1980

[Oral treatment of severe forms of acne with 13-cis-retinoic acid. Clinical results (author's transl)].

A new, very effective method of treating severe forms of acne (papuplopustular, conglobate, fulminating and tetrad) is the oral administration of 13-cis-retinoic acid. The results described by Peck et al. (1979) in 14 patients are demonstrated in detail in 18 patients. In the initial therapy 1 to 2 mg/kg body weight were administered daily for 12 weeks without any other local or systemic treatment. In the second phase of the study half the patients continued treatment with 0.5 mg/kg body weight 13-cis-retinoic acid, the other half remaining without any further therapy. All inflammatory lesions healed after 12-16 weeks, sebum production was largely reduced. 13-cis-retinoic acid represents a remarkable turn in the treatment of most severe acne.

Acne Vulgaris↗
PubMed1981

Acne vulgaris: therapy directed at pathophysiologic defects.

An effective therapeutic regimen for the treatment of acne vulgaris is presented. The emphasis is based upon correcting a defect in keratinization of the sebaceous follicles with a combination of vitamins A and E. This prevents the formation of milia and comedones, thus depriving the Propionibacterium acnes of a culture medium. Vitamin E also prevents irritating lipid peroxidation of sebum, damaged by bacterial growth, which may be responsible for the inflammatory aspects of acne. No antibiotics were employed in the series of 98 consecutive cases examined herein.

Acne Vulgaris↗
PubMed1981

[Oral treatment of rosacea with 13-cis-retinoic acid].

Thirteen patients with severe rosacea (rosacea papulopustolosa, rosacea conglobata, and rhinophyma) were treated orally with 0.05, 0.5, or 1.0 mg/kg body weight 13-cis-retinoic acid (isotretinoin, Ro 4-3780) for 12-28 weeks. All patients had been treated previously with high doses of tetracyclines, metronidazole, or dermabrasion, etc., with no or only limited success. The therapeutic effect following 13-cis-retinoic acid was excellent. Inflammatory lesions regressed by 50% within 2 weeks, and by over 95% within 8 weeks. 13-cis-retinoic acid acts as a potent anti-inflammatory and sebum-suppressive agent. Besides papulopustules, nodules, and hemorrhagic abscesses, the inflammatory plaques and facial edema, but to a lesser extent teleangiectasias and the chronic conjunctivitis disappeared. The severe seborrhea disappeared. Long-lasting remission, similar to patients with severe acne being treated with 13-cis-retinoic acid, can be expected, as the first patients are in full remission for over 12 months at the time of writing. Exfoliative cheilitis occurred in every patient. Serum lipids increased only slightly. For female patients a reliable contraception is mandatory as teratogenicity cannot be excluded in this drug (similar to all retinoids).

Adult↗
PubMed1982

[Histologic study of stimulation of preputial glands in the mouse by androgens and inhibition by a detergent or zinc salts].

Preputial glands are a kind of sebaceous glands ; they play a role in reproduction and sexual and social behavior by means of secreted pheromones. In this work, the authors compared the regression of these glands to that of seminal vesicles and investigated the stimulating potency of three androgens : testosterone, androstenedione, androsterone. These data demonstrate the sensitivity of preputial glands to all three androgens. Castration interrupted the secretory activity of the glandular cells of the acini. Four injections of 250 micrograms of testosterone, nine injections of 250 micrograms of androstenedione or androsterone to male mice castrated before puberty restored elaboration and holocrine secretion of sebum. The authors tested for a possible antagonistic action of two substances : a detergent, superinone (100 mg body weight) and zinc salts (10 mg body weight) associated to androgens. After treatment by superinone, histological analysis revealed glandular cell lysis. The action of zinc salts was less pronounced. Zinc acetate and sulfate seem to counter the elaboration of secretions without disrupting glandular structure. The mechanisms of action of their two substances are very probably different.

Androgens↗
PubMed1978

In vivo changes in the composition of cattle skin surface lipid with time.

The skin surface lipid composition was examined in cattle over a period of 13 days after cleaning the skin at 15 degrees C and 35 degrees C. Little change was observed in the concentrations and fatty acid compositions of all the major sebum fractions other than the unesterified fatty acids. Changes which occurred in the proportions of fatty acids present in the unesterified fatty acid fraction were similar at both environments. At 15 degrees C the total amounts per unit area of unesterified fatty acids on the skin did not alter significantly with time. However, at 35 degrees C there was a significant increase in the total amounts of unesterified fatty acids per unit area and concomitant increases in the amounts of individual fatty acids, in particular linoleic acid.

Animals↗
PubMedDate not supplied

Highlights on the etiology of keloid.

The keloid phenomenon is old and perplexing. Many hypotheses were advanced to account for keloid growth but none of them provided a satisfactory explanation for the clinical manifestations of the disease. To solve the mystery of keloid detailed clinical studies coupled with laboratory tests were undertaken on keloid and non-keloid individuals; these highlighted the determinants of the disease and paved the way to the formulation of the Sebum Auto-immune Theory. The latter provided valid explanations for the clinical manifestations of the disease and indicated a rationale for new trends of management.

Autoimmune Diseases↗
PubMed1994

[Dermatology meeting of Paris. 7-10 December 1994. Abstracts].

In 1994 acne should be a very treatable disorder. However there are a significant number of patients who do not respond as well to therapy as they ought. Compliance is an important reason for poor response. Inappropriate therapy is another common reason. An increasing problem are patients with resistance of P. acnes to commonly used antibiotics; 39% of our patients have such resistance. Within this sub-group the commonest antibiotics causing problems are Erythromycin and Clindamycin (69%). Resistance is seen in 20% of such subjects to Tetracycline and Vibramycin and resistance to Trimethoprim is 12%. Multiple resistance is 14%. This is an increasing problem and unless attention is given to this problem by the year 2,000 we may have very few safe and successful antibiotics. Minocycline is rarely associated with resistance. Some patients have no resistance and may have a high sebum excretion; this will dilute what otherwise could be effective therapy. Such patients ought to be given high dose antibiotics such as Minocycline 200 mgs per day, plus appropriate topical therapy. Dianette plus 50- 100 mg cyproterone remains an alternative therapy in females. Some patients will fail to respond with these regimes and require Isotretinoin. Patients who require oral Isotretinoin are those with non-responding moderate acne, patients who scar, plus patients with unusual but specific problems. These include Acne Fulminans, Rosacea Fulminans, Acne Conglobata, Gram-negative folliculitis, Gross Seborrhoea, Dysmorphophobia, Mature Acne and Aperts Syndrome. The choice of dose varies, often according to personal experience and cost. Most physicians prescribe 0.5-1.0 mg/day for 4 months. Fifteen percent require 5-12 months therapy. Frequent reasons for prolonged therapy are macrocomedones and polycystic ovary syndrome. Relapse post therapy occurs in 30%; relapse after 3 years is unusual. Repeat doses can be given. The results are predictive and successful. The treatment of certain troublesome side effects also will be discussed as will the use of Isotretinoin in systemic disease. Isotretinoin orally is so effective that it ought to be given sooner rather than later to minimise scarring about which still only a little can be done to help the patient.

Animals↗
PubMed1995

[Isotretinoin administration in treatment of acne vulgaris. A prospective study of the kind and extent of ocular complications].

Isotretinoin (13-cis-retinoic acid) is commonly used for the treatment of acne vulgaris. In the skin this substance causes an atrophy of sebaceous gland acini and a decrease in sebum production. Systemic treatment also alters meibomian gland function and structure. These alterations seem to be responsible for ocular complications (dryness of the eye, blepharitis, conjunctivitis) during therapy with isotretinoin. We inspected 30 patients before, during and after therapy with isotretinoin with regard to ocular side effects. Examination included careful slit-lamp inspection, measurement of break-up time (BUT) and the Schirmer test. Conjunctival smears were taken from every patient. The most frequently observed side-effects were decreased tear break up time and alterations of the lid margin. In addition, an enormous increase of Staphylococcus aureus in conjunctival flora was noticed. However, all ocular complications of systemic treatment with isotretinoin were reversible after cessation of therapy.

Acne Vulgaris↗
PubMed1994

[Study on cutaneous physio-immuno-pathological status in tinea versicolor].

This study examined 20 cases of tinea versicolor to assess the dermato-physiological, immunological and pathological status of lesion sites as compared to 20 normal control subjects. Lesion sites showed a significant decrease in sebaceous gland secretions and water content and an increase in pH value compared to normal skin. There was no significant change in involucrin, filaggrin, or number of stratum corneum cell layers. However, lesions showed weak positive staining of IL-1 alpha. A possible mechanism for these changes is that profuse sweat gland secretions predispose to fungal growth and acid mantle destruction, with the pathogens consuming amino acids and sebum as nutrients. Slight increases in IL-1 alpha levels seen in infected areas could be due to a fungus-stimulated immune reaction in the stratum corneum.

Adult↗