News forum: Latest research

GPs with an interest in dermatology review the latest papers of significance from research teams across the world

Skills training for patients in use of the ABCDE criteria
Arch Dermatol 2006; 142: 447-52
The ABCD (Asymmetry, Border irregularity, Colour variegation, Diameter >6mm) criteria were created in 1985 to help doctors and patients differentiate melanomas from benign naevi. The importance of change in shape, size and symptoms, for example, itching and tenderness, led to the addition of an E (Evolution) in 2004, giving us the ABCDE criteria in use today.

This study attempted to teach at-risk patients how to carry out skin self-examination using the ABCDE criteria. One hundred unrelated adults with either a personal or a family history of melanoma were selected and taught self-examination techniques, using projected images and transparencies of moles placed on the forearm.

They were given training by a dermatologist on how to use the ABCDE criteria and were provided with rulers, a size 2 pencil with a rubber (the rubber was placed over the lesion to assess those >6mm), an illuminated magnifying glass, a bookmark and a brochure on how to recognise lesions.

Results showed that patients preferred the simpler bookmark and the magnifying lens to the brochure, as the latter took too long to use. They also preferred the ruler to the pencil once they had been taught how to use the gradations. Patients' ability to recognise border irregularity, colour variegation and diameter significantly improved after training.

Interestingly, women were better at recognising colour variegation (the authors postulated that this might be due to a higher incidence of colour blindness in men) and men were better at assessing border irregularity. Women were also better at referring suspicious lesions.

The authors concluded that although teaching the ABCDE criteria to patients is challenging, skills training can aid the performance of skin self-examination. They also suggested that men and women form partnerships to combine their different strengths and hence promote detection of early melanoma.

  • Dr Waseem Chaudhry is a GPSI in dermatology in Caerphilly

Epidermal barrier formation and recovery in skin disorders
J Clin Invest 2006; 116(5): 1150-8
This review article dealt with the molecular biology of normal and abnormal epidermal function. I have to admit, most of the article was quite heavy going, with references to molecular biology and genetics that were difficult to understand.

However, the underlying theme of the article dealt with the role of the epidermal barrier as a defence mechanism to the external environment.

Impairment of this barrier may contribute to the keratinocyte hyperproliferation and cytokine activation seen in psoriasis. Impaired skin barrier function in atopic dermatitis may also contribute to increased antigen absorption and result in cutaneous hypersensitivity.

In psoriasis and atopic dermatitis, genetic and environmental factors affect the pathogenesis. An intriguing finding from genome screening of these disorders is that multiple loci are coincidental. At least 30 genes on 1 chromosome responsible for encoding proteins that build and regulate the epidermal barrier are linked with psoriasis and atopic dermatitis.

Current treatments, that is, topical steroids and emollients, are aimed at reducing the inflammatory response to epidermal damage and repairing the barrier. The author suggests that future research should be focused on elucidating the molecular response of the keratinocytes to epidermal barrier disruption, which would lead to a better understanding of skin diseases and give us possibilities to develop new therapies. Although she does admit this is a daunting task. WC

Increased risk of developing multiple primary melanoma
Arch Dermatol 2006; 142: 433-8
This paper analysed the 2-year results from a population based study of 354 patients who had been given a confirmed first diagnosis of melanoma.

The results showed that 8% (27) of the patients developed a subsequent melanoma in the first 2 years. This included 6% (20) who developed a new melanoma in the first year. The authors then compared these 27 patients as 'cases', with the remaining 327 as 'controls'. The results showed 3 main findings.

First, an inverse relationship of risk of multiple primary melanoma with multiple blistering sunburn. Second, the number of atypical moles was significantly related to an increase in risk. Third, the presence of 3 or more atypical moles was associated with a more than fourfold increased risk of multiple primary melanoma.

The authors concluded that additional melanomas occur more frequently than previously shown and that atypical moles are strongly associated with a risk of multiple primary melanoma. The surprise finding of an inverse link with blistering sunburn was thought to be due to possible confounding factors.
This study seems to justify the need for regular and frequent follow-up to be provided for patients diagnosed with primary malignant melanoma. WC

Smoking and acne
J Invest Dermatol 2006
Smoking is a major health risk, but there are a few situations where it has appeared to be of benefit, not that we should be encouraging it. Being a smoker is reported to reduce your chances of developing ulcerative colitis, acne rosacea, pemphigus vulgaris and recurrent aphthous stomatitis. It also, according to this study, may have a role in reducing your chances of developing severe acne vulgaris.

The study was designed to investigate a possible relationship between cigarette smoking and severe acne. It was carried out from 1983 to 2003 and involved 27,083 male subjects.

Information was gathered using trained nurses completing questionnaires on young men leaving compulsory military service in Israel. The questionnaire targeted information on family history, habits and tobacco smoking. Their acne was diagnosed and coded by board-certified dermatologists.

Of the subjects, 43%  were smokers, and 237 subjects out of the 27,000 had a diagnosis of severe acne. Of these, the significant majority were non-smokers. They also found an inverse dose-dependent relationship when more than 21 cigarettes a day were smoked; that is, the more you smoked, the less chance you had of developing severe acne.

As the study rightly points out, the researchers were unable to take into account the effects of passive smoking and they did not assess acne treatments being used for those subjects with mild, moderate, or severe acne, so the study could only indicate a possible relationship between smoking and reduced chances of developing severe acne.

So should we now be carrying out more trials to assess the relationship further, or, as suggested in this study, should we be performing trials on topical nicotine treatment for acne to investigate this association? Watch this space.

  • Dr Jane Barnard is a GP in Yateley, Hampshire

Fish worm allergy
J Allergy Clin Immunol 2006; 117(5): 1098-105
I have come across many theories about the causes of dermatitis, but this was a new one on me. To give you some background, there is a small roundworm, commonly known as the herring worm, that occurs in herring, mackerel, whiting and blue whiting, but also in many other species.

The scientific name of this roundworm is Anisakis simplex. It grows up to 2cm long in fish, is almost colourless and is found tightly coiled and encased in the guts and flesh, sometimes in considerable numbers, particularly in the belly flaps.

Its larvae can migrate from guts to flesh in fish left ungutted after capture. If that is not enough to put you off your cod and chips, it seems that fish-processing workers who become infested with it can develop various allergic symptoms, including allergic airway hyperreactivity and dermatitis.

To investigate this possibility further, researchers from the Institute of Infectious Diseases and Molecular Medicine in Cape Town, South Africa, set up a trial to investigate the prevalence of Anisakis simplex sensitisation and related symptoms among workers in 2 fish-processing factories, and used gene-deficient mice to determine the working mechanisms of the allergy.

The research involved measuring eicosapentanoic acid, which appears to be related to your piscatorial ingestion, and injecting the mice with Anisakis simplex extract. I will spare you the small print, but the outcome was that Anisakis-specific IgE was involved in an allergic process.

The authors concluded that Anisakis simplex sensitisation in fish-processing workers is associated with allergic symptoms and correlates with high levels of fish consumption. What I could not establish was whether these findings are unique to South Africa, or whether the problem can occur anywhere. If the latter is the case, should we be asking any patients who present with unexplained allergic symptoms if they work in the fish-processing industry, especially if they hail from South Africa? I did manage to find out that the little devils can survive in raw, salted, lightly smoked, or marinated fish, but are killed by normal cooking or freezing. Oh well, I never did like sushi much, anyway. JB

Assessing the impact of food allergy in childhood eczema
Dermatol Ther 2006; 19(2): 91-6
Food allergy as a cause of eczematous reactions appears to be a popular diagnosis with parents and many healthcare professionals. Despite the fact that food challenge studies show food-induced eczematous reactions are rare, many practitioners believe up to 30% of atopic dermatitis is food-induced.

This leads to enthusiastic and probably largely unnecessary allergy testing. The high false-positivity rate of these tests only serves to encourage parents even more to believe that their offspring's atopic dermatitis is due to a food allergy.

This study looked at children under 11 years old with atopic dermatitis and a suspicion of food allergy. A questionnaire given to the parents was used to assess previous diagnoses, the healthcare provider and testing patterns.

Most of the 38 subjects' parents suspected that food allergy was the cause of their child's atopic dermatitis. Allergy was suggested as the cause by 63% of the healthcare professionals involved. Three-quarters of the patients had allergy testing and 90% of the parents believed their children had food-induced atopic dermatitis.

These findings are clearly at variance with the proven rarity of true food allergy, yet the majority of these children had allergy suggested as a causative agent for their skin problem by their primary care provider.

The point the researchers made was that a consensus about the role of food allergy is needed, so all healthcare professionals are singing from the same hymn sheet when dealing with the management of atopic dermatitis in children. This would save a lot of money and make management more effective. JB

Adrenaline and the use of local anaesthesia near end arteries
J Am Acad Dermatol 2004; 51: 755-9
One of the first and most important rules doctors learn when training to perform minor surgery is that adrenaline should never be used with local anaesthesia when the injection site lies anywhere near end arteries.

These are typically fingers, toes and the penis. The resultant arterial constriction, which normally helps to reduce bleeding, and the duration of anaesthesia leads to tissue necrosis and death distal to the injection site.

The aim of this paper was to perform a comprehensive literature review looking for cases of digital necrosis associated with this practice. The method undertaken was a PubMed search of the National Library of Medicine Database, using the terms lidocaine, epinephrine and finger.

The result was reference to 16 papers, of which 6 dealt with digital anaesthesia. These revealed a total of 50 cases of digital gangrene, mostly in the early part of the previous century.

In 21 of these cases, the gangrene was associated with the use of epinephrine mixed with the local anaesthesia, although the actual concentration used was only reported in 4 cases.

Careful analysis of reported cases did not support epinephrine as the cause; other factors were thought to be contributory, such as older anaesthetic agents, including cocaine, eukaine and procaine, inappropriate use of tourniquets, post-operative hot soaks, infection, or the use of large volumes of anaesthesia.

From this, they concluded that a review of the literature failed to support the longstanding idea that using adrenaline near end arteries leads to distal gangrene. In fact, its use generally reduces the need for tourniquets and large volumes of anaesthesia and provides better and longer pain relief.

Obviously, in the literature search, the authors were looking only for finger gangrene, and whether this paper would be enough to satisfy the GMC if things did inadvertently go wrong, I am not sure; for now, I will not be changing my practice.

In these days of evidence-based medicine, I am afraid that at the moment, there is not enough evidence to support the use of adrenaline anaesthesia in fingers and toes, and in fact, the BNF/MIMS section on anaesthesia still advises against its use.

  • Dr Nigel Stollery is a GP in Kibworth, Leicestershire, and clinical assistant in dermatology at the Leicester Royal Infirmary

Tobacco exposure and allergies in schoolchildren
Respir Med 2006 May 28 (Epub ahead of print)
It is well known that smoking is harmful not only to smokers, but  also to those around them, especially children. But how much parental smoking influences asthma and allergies in children has not been properly evaluated.

This French study looked at 7,798 children of fourth and fifth grade who answered a questionnaire and underwent a medical examination that included skin prick testing, skin examination for eczema and tests to assess exercise-induced asthma.

The researchers took into account family history of asthma, personal atopy, breastfeeding, pet ownership and daycare in the first 6 months of life. In the group of children selected, 25.2% had eczema, 12.9% had rhinitis, 9.9% had asthma and 25% had an atopy; the mothers of 21.6% of children smoked during pregnancy.

The results were inconclusive and surprising. Even though, as expected, maternal smoking during pregnancy and later on was related to lifetime wheezing, there was no association between parental smoking and atopy, rhinitis, or asthma in children.

The authors concluded that parents should still be advised to stop smoking. Not long to go before smoking in the home is banned as well as public smoking. NS

Anxiety and skin allergies
Br J Dermatol 2006; 154: 1128-36
Interestingly, another French study looked at the link between allergic conditions and psychological comorbidities, especially anxiety. In this study, 3,939 patients with allergies, mainly allergic rhinitis, asthma and atopic dermatitis (AD), completed a questionnaire about their conditions and another questionnaire was filled in by their allergy specialist. The researchers used the State (S) and Trait (T) score and the ANCOVA (analysis of covariance) models in relation to current and past disease.

AD had the strongest association with anxiety, with women being most affected. It is to be hoped that this established link instigates a change in the management of patients with AD. Perhaps as GPs, we should also be asking patients with AD about their psychological well-being. NS

A high fat diet reduces the risk of skin cancer
BMC Cancer 2006, 6: 141
Eating a high fat diet might reduce the risk of developing skin cancer, according to researchers in Australia. The findings conflict with previous studies, which suggested that a high fat diet might contribute to an increased risk.
This study included 652 patients with melanoma and non-melanoma skin cancer who were aged 20-59, of northern European ancestry and living in Tasmania, and 472 controls. All participants completed a questionnaire on their intake of dietary fat, as well as information on sun exposure since childhood.

The researchers compared the impact of a low, medium and high dietary fat intake on the risk of having skin cancer.

After adjusting for age, sex and sun exposure, they found that those patients who had the highest dietary fat intake were least likely to have skin cancer.

These patients had a 48% decreased risk, compared to those in the lowest fat intake group. Those with a medium dietary fat intake were 24% less likely to have skin cancer than those with the lowest fat intake. Follow-up data on the rates of new non-melanoma skin cancer over 4 years after the initial study provided further support for a link. NS

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