The clinical and (dermato) pathological signifcance of neural crest cells. Blaschko lines and dermatoses. Neurocristopathies

In the course of their migration the neural crest cells reach all parts of the developing embryo. The frst wave of the derivatives of these cells the melanoblasts and melanocytes harbour in the epidermis and hair follicles during the dorsolateral migration. A number of signal molecules and proteases play an important role in the course of melanocyte migration through the extracellular matrix. The Mongolian spots appear as a consequence of the transient inhibition of melanocyte migration and in the case of fnal obstruction the Ota-, or. Ito nevuses. The Blaschko lines based on cutaneous mosaicism are of great diagnostic importance and on the ground of these lines the blaschkitises can appear under the exogenous factors. The blaschkolinear acquired infammatory skin eruption (BLAISE) is an acquired infammatory process. One of its variants is the lichen striatus and the other is the blaschkitis. The blaschkolinear dermatoses can appear usually as a nevoid disease. The pathological development of the neural crest cells can induce pathological processes in other tissues of the body as well, which may appear in the form of the so-called neurocristopathies including approximately ffty manifestations. The knowledge of the diferent pigmentation forms as well as the pathological symptoms of neurocristopathies is of great importance for the clinican from a diagnostic point of view.

The role, carrier and mission of neural crest cells in the skin

The neuro crest arising from the ectoderm is a transient structure and disappears as the neurocrest cells leave these places to invade the whole embryo. The epidermis develops from the ectoderm in the fourth embryonal weeks. The embryos consist of cranial-,vagal-, truncal and sacral segments and the neuro crest cells migrate from these places to form various structures, including the peripheral nerve system, the craniofacial bones and cartilages, etc. The neuro crest cells degrade the basal membrane of neural tube and thereafter migrate through the extracellular matrix in ventromedial and dorsolateral direction. Neural crest cells use various cell adhesion molecules and diferent proteaes. The invasive capacity of these cells is infuenced by aquaporin-1 , too. . The sensory nerves developig from the neuro- crest cells can be found in the epidermis and its appendicular organ, the dermal autonomic nerves in the dermis. The epidermal melanocytes develop partly from the neural crest cells, partly from the Schwann cells of the sensory nerves. The cutaneous nerves produce and secrete neuropeptides thus contributing to the development of the skin into a neuroimmuno-endocrin organ.

New treatment options of chronic urticaria

Chronic urticaria is a multifactorial disease with increasing prevalence, that significantly deteriorates the quality of life of patients. Authors describe the pathomechanism of the disease, and they present the currently available treatment options and the promising future therapies as well. The therapeutic basis of chronic urticaria is the modern, 2nd generation antihistamines in a dosage of even four times higher than the regular one. In therapy resistant cases omalizumab or cyclosporin is advised. There is a growing demand for new medications because the number of those patients , who are non-responders or do not respond adequately to these therapies, is definitely increasing.

New therapies in atopic dermatitis

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases. Despite of this, the pathomechanism of the disease is still not fully understood. In recent years, several scientific results led to the better understanding of the disease. Meantime, new therapeutical options have emerged which were developed specifically for AD patients. In this manuscript new therapies, namely dupilumab and baricitinib, which are already licenced in Hungary, are reviewed. A detailed description of therapies e.g. biological therapy, small molecular weight drugs, topical therapy and antipruritics which are currently in clinical research have been also summarized.

New therapeutic options in psoriasis

The biological therapy of moderate-to-severe psoriasis has a history of almost two decades. During this period our knowledge of the pathomechanism of the disease has become more accurate, leading to the development of more and more targeted therapies. Increased efficacy through more specific inhibition is accompanied by less adverse events. In this article, the authors summarize the current possibilities for the modern treatment of psoriasis and the key clinical insights into these options. They discuss the future therapeutic directions and new agents.

Prurigo nodularis, prurigo chronica, new therapeutic options

Prurigo nodularis (PN) is a skin disease that develops on chronically itchy skin. There are various causes behind the chronic itch. Due to intensive research in recent years different mechanisms that can participate in the development of chronic pruritus have been discovered, opening up new therapeutic targets for treatment. Here we review the various mechanisms behind chronic pruritus and discuss the novel therapies for PN.

New therapeutic strategies of lichen ruber planus

Lichen ruber planus/lichen planus (LP), is a chronic immune-mediated inflammatory disease that affects the skin, oral mucosa, genital mucosa, scalp and nails. Planar, purple, polygonal, pruritic, papules and plaques appear on the flexor surfaces of the wrists, forearms and legs. Mucosal lesions are often lacy, reticular, white lines known as Wickham striae. Topical corticosteroids are the first-line therapy for all forms of LP, for severe, widespread LP systemic corticosteroids, acitretine, oral immunosuppressants or narrowband UVB therapy should be considered. Cutaneous LP may resolve spontaneously within one or two years, while mucosal LP may be more persistent and resistant to treatment.

New therapeutic approaches in hidradenitis suppurativa

Complex multifactorial pathogenesis of hidradenitis suppurativa eventually results in chronic inflammation of the apocrine gland-bearing areas of the skin. However, the pathogenesis is not fully understood, there are many immune cells and inflammatory pathways of which role is clearly defined in the last years in HS, such as interleukin 1β (IL-1β), tumour necrosis factor alpha (TNFα), IL-17, IL-12 and IL-23. These pathways provide multiple targets for medical treatment. Currently, only adalimumab is licenced in HS, but the numerous ongoing clinical trials promise huge potential therapeutic options in this debilitating disease.

New therapies for alopecia areata

Over the past few years, better understanding of the explicit pathomechanism of alopecia areata provides new treatment opportunities for effective therapy of the disease, which may revolutionize therapeutic strategies. This exceedingly heterogeneous disease with unpredictable outcome, severely affects the quality of life. Currently, there are no standardized treatment protocols approved by the European Medicines Agency (EMA), resulting a challenge for the therapists in the choice of treatment.In this paper, the authors summarize recent and emerging therapies for severe cases of alopecia areata.

Atypical clinical variants, predisposing factors and new therapeutic guidelines in bullous pemphigoid

Bullous pemphigoid is the most common autoimmune subepidermal blistering disease in elderly people. The disease typically manifests on the skin and the mucosa with tense bullae or erosions with surrounding erythema, but in up to 20% of afected patients, bullae may be completely absent. The localized or generalized skin lesions usually present with itch. The author presents the rare, atypical forms of the disease, the most common triggering and predisposing factors, and the new therapeutic recommendations according to the European guidelines.