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Query: UMLS:C0033774 (pruritus)
 14,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dandruff is a major problem, yet little is known about the underlying mechanism and subsequent biochemical changes occurring in the scalp skin that lead to its manifestation. The characteristic flaking and scaling of the scalp experienced by dandruff sufferers suggests, similar to the changes classically seen in xerosis, that the desquamation process is impaired. We initiated studies to quantify the biochemical nature of the stratum corneum in the scalp of healthy individuals and dandruff sufferers. Total amounts and relative ratios of stratum corneum lipids species were analysed in scalp stratum corneum samples collected during studies conducted in the UK and Thailand in order to examine ethnic differences. In both populations, dandruff was associated with a dramatic decrease in free lipid levels, with significant decreases in ceramides, fatty acids, and cholesterol. Detailed sub-analysis of the major ceramide species within the total ceramide fraction revealed a decrease in ceramide 1 and increased proportions of ceramide 6i and 6ii. In a separate study, we demonstrated that dandruff sufferers show both an elevated blood flow and an increased reported incidence of itch in response to histamine topically applied to the scalp compared with no-dandruff controls. Taken together these two studies indicate that the quality and resilience of the epidermal water barrier is impaired in the scalp of dandruff sufferers. We propose that the perturbed barrier leaves dandruff sufferers more prone to the adverse effects of microbial and fungal toxins, and environmental pollutants, thus perpetuating their impaired barrier.
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PMID:Dandruff: a condition characterized by decreased levels of intercellular lipids in scalp stratum corneum and impaired barrier function. 1211 25

The scalp is a unique site of the human body that may exhibit some particular physiopathological reactions. A few manifestations are paroxysmal. The main ones are the acute pruritus of pediculosis, and the pruritus at onset of dandruff or seborrhoeic dermatitis. One must add the telogen effuvium after solar exposure or during the post-partum, and the anagen dystrophic alopecia following chemotherapy. Other paroxysmal events include acute canitia and alopecia areata.
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PMID:[Paroxismal reactions of the scalp]. 1518 24

A 7-year-old girl presented with itching and greyish-white sleeve-like structures in her hair. After ruling out other possible causes for the symptoms, such as nits and dandruff, it was determined that the patient was affected by hair casts. These are small cylindrical structures resembling louse eggs that encircle individual scalp hairs and are easily movable along the hair shafts. It was concluded that she had induced the condition through misuse of a deodorant body spray. Scanning electron microscopy combined with electron dispersive X-ray analysis (X-ray microanalysis) of the hair casts showed the chemical nature of the structures. Some elements present in the composition of the ingredients of the deodorant spray, such as aluminium, chlorine, silicon, magnesium and carbon, were also present in this uncommon type of hair casts.
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PMID:Hair casts due to a deodorant spray. 1619 31

Scalp skin is unique on the body due to the density of hair follicles and high rate of sebum production. These features make it susceptible to superficial mycotic conditions (dandruff, seborrheic dermatitis, and tinea capitis), parasitic infestation (pediculosis capitis), and inflammatory conditions (psoriasis). Because these scalp conditions share similar clinical manifestations of scaling, inflammation, hair loss, and pruritus, differential diagnosis is critically important. Diagnostic techniques and effective treatment strategies for each of the above conditions will be discussed.
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PMID:Clinical diagnosis of common scalp disorders. 1638 61

Most common scalp flaking disorders show a strong correlation with sebaceous gland (SG) activity. Early SG activity in the neonate results in microfloral colonization and cradle cap. After maternal hormonal control subsides, there is little SG activity until puberty, when the SG turns on under sex hormone control. When the SG activity increases, the present but low Malassezia population has a new food source and proliferates, resulting in the scalp itching and flaking common to greater than 50% of adults. Dry scalp flaking, dandruff, and seborrheic dermatitis are chronic scalp manifestations of similar etiology differing only in severity. The common etiology is a convergence of three factors: (1) SG secretions, (2) microfloral metabolism, and (3) individual susceptibility. Dandruff and seborrheic dermatitis (D/SD) are more than superficial stratum corneum disorders, including alteration of the epidermis with hyperproliferation, excess lipids, interdigitation of the corneal envelope, and parakeratosis. The pathogenic role of Malassezia in D/SD has recently been elucidated, and is focused on their lipid metabolism. Malassezia restricta and M. globosa require lipids. They degrade sebum, free fatty acids from triglycerides, consume specific saturated fatty acids, and leave behind the unsaturates. Penetration of the modified sebaceous secretions results in inflammation, irritation, and scalp flaking.
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PMID:The role of sebaceous gland activity and scalp microfloral metabolism in the etiology of seborrheic dermatitis and dandruff. 1638 62

Dandruff is a chronic condition of the scalp requiring vigilant treatment to ameliorate the symptoms of scaling and itching. Frequent shampooing is key to controlling these symptoms while contributing to the cosmetic appearance of the hair. The success of the treatment depends not only on the ability of the shampoo to control the dandruff but also on patient compliance engendered by the cosmetic attributes of the shampoo. This double-blind cross-over study enrolled 40 women with mild to moderate dandruff. Following a 1-wk washout with an unmedicated basic cleansing shampoo, all subjects used each of the two study shampoos for 1 wk. Subjects preferred the 1% pyrithione zinc conditioning shampoo over the 2% ketoconazole shampoo by 75% in terms of overall performance. The dermatologist investigator confirmed the subject preference by noting that hair-combing ease, hair smoothness, and hair frizz/flyaway were statistically significantly better in subjects who used the 1% pyrithione zinc conditioning shampoo for 1 wk. This study suggests that hair condition is an important consideration in the treatment of dandruff due to compliance.
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PMID:A comparison of hair quality and cosmetic acceptance following the use of two anti-dandruff shampoos. 1638 64

Application of new molecular and biochemical tools has greatly increased our understanding of the organisms, mechanisms, and treatments of dandruff and seborrheic dermatitis. Dandruff results from at least three etiologic factors: Malassezia fungi, sebaceous secretions, and individual sensitivity. While Malassezia (formerly P. ovale) has long been a suspected cause, implicated by its presence on skin and lipophylic nature, lack of correlation between Malassezia number and the presence and severity of dandruff has remained perplexing. We have previously identified the Malassezia species correlating to dandruff and seborrheic dermatitis. In this report, we show that dandruff is mediated by Malassezia metabolites, specifically irritating free fatty acids released from sebaceous triglycerides. Investigation of the toxic Malassezia free fatty acid metabolites (represented by oleic acid) reveals the component of individual susceptibility. Malassezia metabolism results in increased levels of scalp free fatty acids. Of the three etiologic factors implicated in dandruff, Malassezia, sebaceous triglycerides, and individual susceptibility, Malassezia are the easiest to control. Pyrithione zinc kills Malassezia and all other fungi, and is highly effective against the Malassezia species actually found on scalp. Reduction in fungi reduces free fatty acids, thereby reducing scalp flaking and itch.
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PMID:Three etiologic facets of dandruff and seborrheic dermatitis: Malassezia fungi, sebaceous lipids, and individual sensitivity. 1638 85

Dandruff is a common complaint and is suffered by as many as 50% of the population at some time during their life and cause significant discomfort. The condition is generally characterized by the presence of flakes on the scalp and in the hair, and by itch. The symptoms can vary, and the severity can range from mild scaling, similar to dry skin, to severe scaling. Its prevalence and severity is greatest in young men, with children and older individuals suffering less frequently. It is commonly aggravated by changes in humidity, trauma (e.g., scratching), seasonal changes, and emotional stress. Dandruff responds to everyday shampooing and a longer period of lathering. Use of hair spray or hair pomades (gels) should be stopped. Salicylic acid, tar, selenium, sulfur, and zinc all are effective in shampoos and may be alternated. Overnight occlusion of salicylic or urea oil may help to soften thick, scalp plaques. The common causative agent is now accepted to be the lipohilic yeasts Malassezia spp. (previously Pityrosporum) which is increased in the scaly epidermis of both dandruff and seborrhoeic dermatitis sufferers. Selenium sulfide, imidazoles or ciclopirox olamine shampoos may help by reducing Malassezia scalp reservoirs. The wide range of antifungal shampoos available provides safe, effective and flexible treatment options for dandruff.
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PMID:[Modern management of dandruff]. 1661 52

Seborrheic dermatitis (SD), a common dermatosis associating hyperseborrhea, erythema, itching, and dandruff, has frequent scalp involvement. Malassezia furfur infection seems to play an important role in the condition's etiopathology. Treatment of SD usually consists of corticosteroids or antifungals, such as ketoconazole. The aim of this multicenter, randomized, investigator-blinded, parallel-group pilot study was to evaluate the efficacy and safety of clobetasol propionate shampoo 0.05% after different short-contact application times compared with its vehicle and ketoconazole foaming gel 2% in the treatment of SD of the scalp. For 4 weeks, 55 subjects received one of the following treatments twice weekly: clobetasol propionate shampoo for 2.5, 5, or 10 minutes; clobetasol propionate vehicle for 10 minutes; or ketoconazole foaming gel for 5 minutes before rinsing off. Efficacy criteria included total severity score (TSS) and individual scores of signs such as itching and global improvement. Safety included reporting of burning, overall tolerance, and adverse events. Results showed that an application of clobetasol propionate for 5 and 10 minutes provided a similar mean percentage decrease of TSS, and the mean percentage decrease of TSS for all active groups was significantly superior to that of the vehicle (P < .01). Overall and local safety were good for all treatment groups. The present pilot study demonstrated that a short-contact application of clobetasol propionate shampoo is effective and safe in the treatment of SD of the scalp.
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PMID:Clobetasol propionate shampoo 0.05% in the treatment of seborrheic dermatitis of the scalp: results of a pilot study. 1756 4

Dandruff is a common scalp disorder affecting almost half of the postpubertal population of any ethnicity and both genders. It may, however, represent a stubborn esthetical disturbance often source of pruritus. Skin biocenosis, in particular the Malassezia spp. flora, plays a key aetiologic role, in combination with the unusual capacity of some corneocytes to be coated by these yeasts. Substantial evidence indicates that keratinocytes play an active role in the generation and expression of immunopathological reactions. This is probably the case in dandruff. Upon stimulation of a critical colonization of corneocytes by Malassezia yeasts, the release of pro-inflammatory mediators is increased. This could lead to the subclinical microinflammation present in dandruff. In seborrheic dermatitis, local deposits of immunoglobulins and the release of lymphokines are responsible for the recruitment and local activation of leukocytes leading to the eventual amplification of the inflammatory reaction. Some ancillary non-microbial causes of dandruff may operate through physical or chemical irritants. Many methods have been described for rating dandruff. Our favourite tools are clinical examination and squamometry. Dandruff can precipitate telogen effluvium and exacerbate androgenic alopecia. Antidandruff formulations exhibiting some direct or indirect anti-inflammatory activity can improve both dandruff and its subsequent hair cycle disturbance.
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PMID:Revisiting dandruff. 1848 95


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