The paradigm shift in dermatology for the last day of the Paris congress

From inflammation to auto-inflammation, from naevi to pigmentary mosaicism, the microbiota… The paradigm shift in dermatology was a thrilling topic for this last working morning, but our three reporter dermatologists were also attentive to other subjects.

Laboratoire BIODERMA maintained its support for the profession with more than 60 posters presented during the congress, thanks to Publi-Assist, and a prize awarded to the work by Agnès Schwieger-Briel on Saturday. The next ESPD congress will be held in Palma de Mallorca on October 2017. We will be there, along with the Pack Info Live, and hope you will be too!

Vitiligo

Dr Khaled Ezzedine reminded us that vitiligo is a paediatric disease occurring before the age of 20 in 2/3 of cases.

There is segmental and non-segmental vitiligo; in the non-segmental form, there is:

  • Later and gradual onset;
  • Delayed depigmentation of body hair;
  • Frequency of halo naevi;
  • Association with auto-immune diseases;
  • Family history;
  • Significance of the Koebner phenomenon.

The efficacy of treatments is inconstant; the criteria for improved response are recentness, facial vitiligo and a dark phototype:

  • The treatment of progressive forms includes: oral minipulse therapy with corticosteroids (dexamethasone 2.5 mg/day, twice a week for three to six months), combined with 308 nm excimer laser sessions for localised forms or UVB TL01 phototherapy for diffuse forms;
  • Given the high risk of recurrence regardless of the treatment, a maintenance treatment is legitimate. Topical tacrolimus 0.1% twice a week for six months has shown efficacy;
  • Repigmentation of vitiligo in patients treated with JAK 1-3 inhibitors provides therapeutic hope over the medium term.

Congenital naevi

Professor Veronica Kinsler reviewed the role of NRAS gene mutations in giant congenital naevi. Mutations in this gene are responsible for loss of negative feedback resulting in the activation of the cell signalling pathways regulated by NRAS. A mouse model was recently developed. This model was used to evaluate an MEK inhibitor (trametinib). After six injections, the mice showed a decrease in cutaneous and cerebral lesions.

Moreover, the speaker presented a case in which a healthy area of skin appeared in a congenital naevus. According to the work that was presented, this correction may have been caused by an 'epigenetic reverting mosaicism' mechanism. This assumption needs to be confirmed by work in progress.

Professor Suzanne Pasmans underlined difficulties in issuing recommendations on the treatment of congenital naevi:

  • Large congenital naevi are rare: 1/20,000 births for naevi with a diameter of 20 to 40 cm and only 1/500,000 above 40 cm;
  • The occurrence of melanoma on CN is estimated at 0.7% all sizes combined, but this risk increases significantly with size; it is estimated at 2% for 20-40 cm naevi and 10% for naevi of over 40 cm. These are primarily dermal melanomas whose differential diagnosis with benign proliferative nodules is clinically and histologically difficult;
  • There is risk of neurocutaneous melanosis in two situations:
    - If isolated CN > 20 cm;
    - If more than 3 CN over 1.5 cm;

An MRI is recommended in these situations.

Prophylactic removal is complicated in the most at-risk situations and does not reduce the risk of melanoma. Semi-annual follow-up is recommended with a close cutaneous examination and the systematic palpation of lymph nodes.

Аtopic dermatitis

During the second session on atopic dermatitis (AD), Thomas Luger insisted on the importance of treating infants as early as possible and the benefits of proactive treatment after flare-ups with tacrolimus or dermocorticoids, twice a week for at least three months.

It has been shown that daily application of an emollient from birth has a preventive effect on AD. Two studies, in the USA+UK and in Japan, respectively analysed 124 and 118 newborns at high risk for AD. The results at six months showed a 50% decrease in the incidence of AD in the USA-UK and a 32% decrease in Japan.

Over 15 years after calcineurin inhibitors (tacrolimus) were first placed on the market, patient follow-up is reassuring with:

  • Demonstrated efficacy in adults and children;
  • No skin barrier impairment
  • No cutaneous atrophy, even over the long term;
  • No proven link with the occurrence of lymphoma or skin cancer.

Promising treatments?

  • Crisaborole, a phosphodiesterase 4 inhibitor, was studied in topical form, 2%. Two multi-centre, double-blind trials versus an excipient analysed over 1500 patients over the age of two years; the results at one month showed a difference similar to that observed in reference studies on tacrolimus;
  • Substance P-receptor (neurokinin 1 receptor or NK1R) antagonists have demonstrated their efficacy on itching of inflammatory origin. Aprepitant and serlopitant are promising;
  • Of the various biological treatments that have been studied, Dupilumab, which acts on TH2 cytokines, is highly attractive. In a placebo-controlled study of 64 adults with moderate to severe AD, the decrease in itching was rapid after ten days; after three months, a very significant improvement in the signs of AD was noted.

Autoimmune bullous diseases

Dr Emmanuel Laffitte gave an overview of autoimmune bullous diseases in children. Childhood bullous pemphigoid is very rare with a main peak in incidence before the age of one year.

  • Before one year, the primary affected regions are the hands and feet;
  • In older children, lesions are predominant on the face and genital region;
  • The prognosis is very good with recovery in 93% of cases after one year in a series of 81 patients undergoing treatment;
  • All of the cured children had no anti-BP180 antibodies;
  • Dermocorticoids remain the first-line treatment and if therapy proves insufficient, they are combined with dapsone with good tolerance.

Linear IgA dermatosis mainly affects older children and adolescents:

  • The lesions are located on the perineum and thighs;
  • The mucous membranes are affected in 60% of cases;
  • The condition is chronic with frequent relapses;
  • There are forms induced by medications, in particular vancomycin;
  • Dapsone is the first-line treatment.