Is there a ‘gut–brain–skin axis’?

Please cite this paper as: Is there a ‘gut–brain–skin axis’? Experimental Dermatology 2010; 19: 401–405. Abstract: Emerging evidence arising from interdisciplinary research supports the occurrence of communication axes between organs, such as the brain–gut or brain–skin axis. The latter is employed in response to stress challenge, along which neurogenic skin inflammation and hair growth inhibition is mediated. We now show that ingestion of a Lactobacillus strain in mice dampens stress‐induced neurogenic skin inflammation and the hair growth inhibition. In conclusion, we are introducing a hypothesis, encouraged by our pilot observations and resting upon published prior evidence from the literature, which amalgamates previously proposed partial concepts into a new, unifying model, i.e. the gut–brain–skin axis. This concept suggests that modulation of the microbiome by deployment of probiotics can not only greatly reduce stress‐induced neurogenic skin inflammation but even affect a very complex cutaneous phenomenon of (mini‐) organ transformation, i.e. hair follicle cycling. These observations raise the intriguing prospect that feeding of just the right kind of bacteria can exert profound beneficial effects on skin homoeostasis, skin inflammation, hair growth and peripheral tissue responses to perceived stress.     

What’s new in acne? An analysis of systematic reviews published in 2009–2010

This review highlights clinically important findings about acne treatment identified in nine systematic reviews published or indexed in the period March 2009 to February 2010. A systematic review of dietary influences on acne suggested that a possible role of dietary factors in acne cannot be dismissed, as the studies to date have not been sufficiently large or robust. Another review looked at benzoyl peroxide, which may be enjoying a comeback because of increasing bacterial resistance to antibiotics, and suggested that there was a lack of evidence that stronger preparations were more effective than weaker ones. The same team also carried out a systematic review addressing the question of whether topical retinoids cause an initial worsening of acne. They found no evidence to suggest initial worsening of acne severity, although there was evidence of skin irritation that typically settled by 8–12 weeks. A review of oral isotretinoin and psychiatric side‐effects reinforced a possible link between the two, although it pointed out that the better‐quality primary studies were still inconclusive. An updated Cochrane Review confirmed the efficacy of combined oral contraceptives (COCs) in reducing acne lesion counts. It also found that the evidence to support COCs containing cyproterone acetate over others was very limited. Another Cochrane Review failed to show any benefit of spironolactone for acne, based on limited studies. Three reviews examined laser and light therapies, and found some evidence of superiority only for blue or blue/red light treatment over placebo light, but a general absence of comparisons against other acne treatments. Photodynamic therapy had consistent benefits over placebo but was associated with significant side‐effects and was not shown to be better than topical adapalene.     

Granuloma annulare – a manifestation of infection with Borrelia?

Background: Among the theories of origin of granuloma annulare (GA) are those of infection. Reports gave raise to the assumption that there is evidence for Borrelia as the causing agent. Methods: To assess the evidence for infection with Borrelia in GA, tissue sections were stained with a polyclonal Borrelia antibody. With focus‐floating microscopy (FFM), slides were scanned at a 200‐ to 400‐fold magnification. Part of the material was also investigated with a Borrelia‐specific polymerase chain reaction (PCR). Results: A total of 157 biopsies of GA have been investigated. Using FFM, Borrelia were detected in 127 cases of GA (80.9%). Borrelia were more prominent in localized (85.2%) than in diffuse GA (62.1%). In 27 cases of GA analysed by PCR, Borrelia‐specific DNA could be detected in only one case (3.7%), but was positive in 21 cases by FFM (77.8%). About 93.3% of 15 control cases of borreliosis were positive with FFM and 46.7% with PCR, while all controls other than borreliosis remained negative for spirochetes. Conclusion: FFM is a reliable method to show Borrelia in tissue sections of GA, which is more sensitive than PCR. This underlines the possibility that Borrelia are involved specifically in the aetiology and pathogenesis of GA.     

Systemic therapy for metastatic malignant melanoma – from deeply disappointing to bright future?

Abstract:  The last decade has seen a considerable improvement in the understanding of the biology of melanoma. Advances have come in the understanding of the importance of critical oncogenes and tumour suppressor genes, epigenetic phenomena, signalling pathways, drug resistance mechanisms, the pivotal role of the local immune system, and the importance of cell–cell and cell–matrix interactions. Many of these pathways and interactions include potentially 'drugable' targets. These developments have allowed the identification and/or design of a range of new, targeted therapies. Evaluation of these new drugs has brought a whole new series of challenges. These include indentification of appropriate pre-clinical models, overcoming the redundancy inbuilt in complex biological systems, identification of appropriate molecular and clinical endpoints to show that the drug is hitting the target, how to combine treatments, and new toxicities. For the first time, there is the possibility of personalised treatment for melanoma patients, based on individual host and tumour characteristics. This paper discusses the range of new drugs and targets have been identified, the outcome of clinical trials, and the directions for future advances.     

What’s new in atopic eczema? An analysis of systematic reviews published in 2009–2010

This review provides a summary of key findings from 18 systematic reviews on atopic eczema, published or indexed between January 2009 and 24 August 2010. There was no good evidence on the possible benefit of organic food consumption and eczema. Maternal intake of fish or fish oil may be associated with a reduced risk of eczema in offspring, although further studies are needed. There is some evidence that partially hydrolysed infant formulas rather than standard formulas may be associated with a reduced risk of eczema in infants, but there are shortcomings in the existing evidence. An inverse relationship has been found between gliomas/acute lymphoblastic leukaemia and allergic disease/eczema, but there appears to be no association between multiple sclerosis and eczema. Attention deficit hyperactivity disorder does appear to be associated with eczema, but there is no evidence of a causal link. The risk of eczema seems to be increased in urban compared with rural areas. Some new evidence has suggested superiority of 1% pimecrolimus over potent and mild corticosteroids at 6 months but not 12 months, and there is some evidence for superiority of 0.03% and 0.1% tacrolimus over 1% pimecrolimus. An updated Cochrane Review still found no evidence of a benefit from any form of antistaphylococcal treatment in managing clinically infected or uninfected eczema. The evidence base is poor for bath emollients, occlusive treatments (e.g. wet and dry wraps) and woven silk clothing in treating eczema. In general, the methods used in most systematic reviews of eczema need to be reported more clearly, especially with regard to a more vigorous quality assessment of included studies. Included studies are frequently heterogeneous, proxy reporting is common, and appropriate disease definitions are often lacking. Better adherence to existing guidance on trial reporting and prospective registration of clinical trials may help improve the quality of studies.     

What’s new in psoriasis? An analysis of guidelines and systematic reviews published in 2009–2010

This review summarizes key clinical findings from 5 guidelines and 21 systematic reviews on psoriasis published or indexed in the period November 2009 to October 2010. The highlights include the British Association of Dermatologists guidelines on the use of biological interventions in psoriasis, and guidelines on the efficacy and use of acitretin. Biological therapies were reviewed for use in specific patient groups (such as those with hepatitis C) and from a health-economics perspective. Another systematic review focused on outcome measures used to assess the severity of psoriasis. Finally, comorbidities including cardiovascular risk were the topic of four systematic reviews.     

Linear lupus panniculitis of the scalp presenting as alopecia along Blaschko’s lines: A distinct variant of lupus panniculitis in East Asians?

A 32-year-old Taiwanese man presented to our clinic with a 6-month history of linear hair loss in a wavy and curved pattern across the parietal and occipital scalp, resembling the distribution of Blaschko's lines. Physical examination showed interfollicular erythema and follicular plugging without skin atrophy or sclerotic change. Histopathology revealed a lymphoplasmacytic infiltrate in the perifollicular dermis and subcutis with abundant mucin deposition, consistent with the diagnosis of lupus panniculitis. Treatment with hydroxychloroquine and local steroid injection resulted in complete hair regrowth but recurrence was noted. Linear lupus panniculitis of the scalp presenting as alopecia along Blaschko's lines had so far been reported exclusively in five East Asians. Apart from classical lupus panniculitis, it had distinct clinical and histopathological features such as younger age of onset, male predominance, reversible clinical course without scarring, fewer associations with systemic lupus erythematosus, exclusive involvement of scalp, sparse inflammatory infiltration, abundant mucin deposition, higher degree of hyaline fat degeneration and negative results of immunofluorescent studies. Therefore, we propose linear lupus panniculitis of the scalp to be a distinct variant of lupus panniculitis and should be included in the differential diagnosis for focal or linear alopecia, especially in East Asians.     

Does the minimal phototoxic dose after 8‐methoxypsoralen baths correlate with the individual’s skin phototype?

BACKGROUND/AIMS: Up to now no data have been available concerning whether there is a significant correlation between skin phototypes and the minimum phototoxic dose (MPD) after bath water delivery of 8-MOP. METHODS: The skin phototype of each of 46 patients was determined based on the individual past history of solar-induced burning and tanning. In addition, the MPD of each patient was assesed after photosensitization with a warm water bath (37 degrees C, 98.6 degrees F) containing 1.0 mg/l 8-methoxypsoralen (8-MOP). Statistical analysis was performed using a Mann-Whitney U-test and Spearman rank order correlation. RESULTS: The median MPD in patients with skin phototype II was 2.0 J/cm2 (range < or =0.5 to > or =3.5) versus 1.5 J/cm2 (range 1.0 to > or =3.5) in patients with skin phototype III. There was a considerable overlap between both groups. No significant difference was detected comparing both groups (P=0.7326) and Spearman rank order correlation revealed no correlation between skin phototype and MPD. CONCLUSION: Erythemal sensitivity in PUVA bath therapy, measured as MPD, is not correlated with sun-reactive skin phototype in skin types II and III. Thus skin phototype is not a suitable indicator for the initial UVA dose in PUVA bath photochemotherapy.     

What’s new in skin cancer? An analysis of guidelines and systematic reviews published in 2008–2009

This review summarizes clinically important findings from 17 systematic reviews and 2 guidelines on skin cancer indexed between April 2008 and April 2009. Melanoma primary-prevention measures, such as education, are more likely to be successful in younger children than adolescents, and general population screening for melanoma by whole-body examination is not currently supported by the evidence. A large systematic review of melanoma and pregnancy concluded that pregnancy does not affect prognosis. Two systematic reviews imply that sunburn later in life also increases the risk of melanoma, and that it is just as important as sunburn early in life. Three systematic reviews discussed the role of positron emission tomography and sentinel lymph-node biopsy for melanoma staging, but produced conflicting results. Superior diagnostic accuracy of dermatoscopy over naked-eye examination for melanoma was found in one review, while a second implied nonsignificantly higher sensitivity of computer-based diagnostic methods over dermatoscopy for melanoma but with reduced specificity. There were no identified randomized controlled trials of treatments for unresectable recurrent melanoma, and a review of immunotherapy with vaccines for melanoma failed to prove improved overall and disease-free survival. Guidelines for the management of basal cell carcinoma call for risk stratification, based on numerous factors including tumour size, site and histological subtype. Squamous cell carcinoma of the ear has been shown to spread to regional lymph nodes more commonly than to other sites, and may be predicted by depth of invasion, tumour size, cellular differentiation and completeness of excision.