Covid-19 dermatoses: Acral vesicular pattern evolving into bullous pemphigoid.

Bullous pemphigoid (BP) appears to be rising in incidence across the Western World, especially in the elderly. Some of the pathogenetic mechanisms involving antigen mimicry and antibody cross-reactivity have been elucidated for cases associated with neurological disease and certain drugs. There have been reports of cutaneous manifestations of Covid-19 (SARS-Cov2 infection) as the pandemic has raged across the world. We report here a case of prolonged Covid-19, symptomatic with dermatoses only, which was seen to evolve initially from a maculo-papular exanthema with acral vesicular dermatitis, into classical BP disease. This was confirmed histologically by positive skin autoantibody serology, direct IMF on peri-lesional skin and also salt-split IMF. Although possible that the development of BP could be a purely co-incidental finding during Covid-19, we suggest that it is more likely that prolonged SARS-Cov2 infection triggered an autoimmune response to the basement membrane antigens, BP 180 and 230. To our knowledge, this is the first case of BP developing during concurrent Covid-19 disease. It will be necessary to continue dermatological surveillance as the pandemic continues, to collate data on BP incidence and to test these patients for Covid-19 disease. As the pandemic continues, even potential and rare associations such as this will be clarified eventually. What's already known about this topic? Covid-19 disease has been associated with a spectrum of dermatosesCommon presentations in up to 20% of patients include exanthema, pseudo-chilblain like acral lesions 'Covid toes', livedo-/retiform purpuric/necrotic vascular lesions, acute urticarial lesions, and vesicular/varicella-like lesionsA multi-system inflammatory syndrome in children akin to Kawasaki syndrome has been described What does this study add? To our knowledge, this is the first description of classic Bullous Pemphigoid evolving from vesicular lesions caused by prolonged SARS-Cov2 induced skin inflammation.

The role of cutaneous dendritic cells in the immunopathogenesis of atopic dermatitis.

We review the immunology of atopic dermatitis (AD) and focus attention on the role of cutaneous dendritic cells. AD is a complex immune-mediated skin disorder characterized by the recruitment of both CD4+ and CD8+ T cells into the skin. T-helper (Th) 2-type cytokines are dominant in acute AD skin, while both Th1- and Th2-type cytokines are present in chronic AD. Cutaneous dendritic cells, which are present in increased numbers within AD skin, are believed to play a key part in the activation of T cells in the skin. They may also help to determine the pattern of cytokines produced by activated effector T cells.

Nail melanoma: a review of the literature with recommendations to improve patient management.

In this review, the current state of knowledge concerning nail melanoma is summarized. The pathogenesis, histological findings, clinical presentation, treatment and prognosis of this rare form of cutaneous melanoma are discussed. Important clinical clues to the early diagnosis of nail melanoma are highlighted and recommendations to improve the management of patients are suggested.

Mohs micrographic surgery for the treatment of in situ nail apparatus melanoma: a case report.

Nail apparatus melanoma (or subungual melanoma) is rare and accounts for only 1.4% of all cutaneous melanomas in the United Kingdom. We report the use of fixed-tissue Mohs micrographic surgery to treat a biopsy-proven Clark level I in situ nail apparatus melanoma, presenting with diffuse longitudinal melanonychia.

The incidence and prognosis of nail apparatus melanoma. A retrospective study of 105 patients in four English regions.

Our population-based study establishes epidemiological data on age-specific incidence rates, clinical presentation, Breslow microstaging, treatment and survival of nail apparatus melanoma (NAM) patients in England. Four cancer registries, covering a population of 10.6 million, recorded 105 cases of NAM during the period 1984-93. During the same decade there was a total of 7585 patients with cutaneous melanoma and NAM represents 1.4% of all cutaneous melanoma. The incidence rate of NAM in English patients is 0.1 per 100,000 of the population per annum. Amelanotic melanoma was the clinical presentation in 24 of our NAM cases. The overall prognosis is poor with an observed 5 year survival of only 51%. Patients with NAM less than 2.5 mm Breslow depth have a 5 year survival of 88% and are twice as likely to survive compared with those with tumours greater or equal to 2.5 mm in thickness (P < 0. 05). NAM patients are best managed by a multidisciplinary team approach in a few key skin cancer centres.

The association of HLA-DQ7 with bullous pemphigoid is restricted to men.

This study examines in detail the HLA associations of 74 patients (40 women and 34 men) with bullous pemphigoid (BP) and compares their immunogenetic profile with that of 604 unrelated control subjects (238 women and 366 men). Correlations were sought between HLA antigens and the various BP disease parameters investigated. The presence of milia was the only clinical or laboratory finding which was linked with a specific HLA antigen, HLA-DQ6, in both men and women with BP (P < 0.01). BP has previously been linked with the HLA-DQ7 antigen and this association was confirmed in 39 of our patients (14 women and 25 men). Twelve of these patients (four women and eight men) were homozygous for HLA-DQ7. The association of HLA-DQ7 with BP was gender-restricted and only significant for men (P < 0.01). No equivalent HLA disease susceptibility risk factor could be identified for our female BP patients. This difference in HLA association between men and women with BP has not been reported previously, and its significance for disease pathogenesis is not known. No specific link could be found between HLA-DQ7 and BP for any of the clinical, immunofluorescence, western blotting, treatment or prognostic disease factors studied.

Cutaneous reactivity of the hands in nickel-sensitive patients with hand eczema.

This study compares the cutaneous reactivity between the hand and the back for 7 female patients with active hand eczema, who were found to be nickel-sensitive on routine patch testing with the European standard series. Patients were patch tested to a dilution series of nickel sulfate on the back in order to determine the threshold concentration for elicitation of allergic contact dermatitis, and based upon this result a lower concentration of nickel was then used for patch tests on the hand. We found that in the majority of patients (6/7) the cutaneous responsiveness of the hand was not increased compared with that of the back. However, the hand of 1 patient was more sensitive to nickel and patch testing was accompanied with a flare of her eczema, which suggests that cutaneous hyperreactivity may be important in individual patients with hand eczema.

Bullous pemphigoid evolving into cicatricial pemphigoid?

We describe three patients who initially presented with both clinical and immunological findings to support a diagnosis of bullous pemphigoid but whose subsequent course has been that of cicatricial pemphigoid. Mucosal scarring was accompanied by a fall in autoantibody titres in our three patients. These cases illustrate the difficulties clinicians may experience in assigning a specific diagnosis to patients. They also support the concept that bullous pemphigoid and cicatricial pemphigoid are part of a single disease spectrum. The most intriguing question is what specific factors determine the expression of a particular disease phenotype as bullous pemphigoid and cicatricial pemphigoid share target antigens and also the DQ7 allele.