Lichen striatus (blaschkitis) following varicella infection

COVID-19 Vaccine-Induced Lichenoid Eruptions-Clinical and Histopathologic Spectrum in a Case Series of Fifteen Patients with Review of the Literature

Lichen planus is a distinctive mucocutaneous disease with well-established clinical and histopathologic criteria. Lichenoid eruptions closely resemble lichen planus and may sometimes be indistinguishable from it. Systemic agents previously associated have included medications, viral infections and vaccines. Sporadic case reports of lichen planus and lichenoid reactions associated with COVID-19 vaccines have recently emerged. Herein, we review the world literature (31 patients) and expand it with a case series of 15 patients who presented with vaccine-induced lichenoid eruption (V-ILE). The spectrum of clinical and histopathologic findings is discussed with emphasis on the subset whose lesions manifested in embryologic fusion lines termed lines of Blaschko. This rare Blaschkoid distribution appeared in seven of the 46 patients studied. Of interest, all seven were linked to the mRNA COVID-19 vaccines. We believe that all lichenoid eruptions should be approached with a heightened index of suspicion and patients should be specifically questioned with regards to their vaccination history. When diagnosed early in its course, V-ILE is easily treated and resolves quickly in almost all patients with or without hyperpigmentation. Additional investigative studies regarding its immunopathology and inflammatory signaling pathways may offer insight into other Th1-driven autoimmune phenomena related to COVID-19 vaccination.

Adult Blaschkitis With Lichenoid Features and Blood Eosinophilia

There have been many reports of congenital and acquired dermatoses that trail Blaschko lines. Lichen striatus is representative of an acquired cutaneous linear inflammatory dermatosis running along the lines of Blaschko, characterized histopathologically by the predominance of lichenoid infiltration. Adult blaschkitis, however, is considered under the same disease spectrum as lichen striatus and is characterized by a spongiotic reaction pattern. Few differences have been recognized between lichen striatus and adult blaschkitis such as age of onset, triggers, distribution, histopathology, and response to treatment.

A case of male patient with adult blaschkitis presenting as unilateral asymptomatic erythematous edematous papules, papulovesicles, and plaques over Blaschko’s lines, in which skin biopsy revealed coexistent pathological features of lichen striatus and adult blaschkitis along with blood eosinophilia, has been presented here. This may add to the cumulative evidence on the pathogenesis of adult blaschkitis as an allergic reaction to an unknown inciting allergen.

Evidence to consider adult blaschkitis as part of the lichen striatus spectrum is growing. Triggers for such skin reactions remain diverse. This case presentation suggests that adult blaschkitis could be triggered by an allergic response evidenced by the blood eosinophilia when other causes of eosinophilia are excluded.

Blaschkolinear Acquired Inflammatory Skin Eruption (BLAISE): Case Report of a Young Man Whose Dermatosis had Features of Lichen Striatus and Blaschkitis

Cutaneous conditions can follow Blaschko’s lines on the skin, which are thought to reflect patterns of cell migration and clonal expansion during embryonic development of the epidermis. These diseases are hypothesized to be caused by genetic mosaicism resulting from processes such as lyonization or somatic postzygotic mutation. Lichen striatus and blaschkitis are two such acquired inflammatory skin disorders that are distinguished in the literature by age of onset, location, and histopathological features. Lichen striatus is typically observed on the extremities of children and is characterized by lichenoid papules that appear in a linear distribution along Blaschko’s lines. Microscopic examination typically shows spongiosis, as well as lichenoid and periadnexal inflammation. Blaschkitis more commonly occurs in adults and frequently involves the truncal areas, including the chest and abdomen. Microscopic examination typically shows spongiotic dermatitis. We describe a young man with a linear eruption extending from the flexor aspect of his right wrist to his central chest, which has features of both lichen striatus and blaschkitis. Both lichen striatus and blaschkitis are self-limited diseases that may resolve within months. It has been suggested that lichen striatus and blaschkitis are not separate entities, but rather the two endpoints within the spectrum of blaschkolinear acquired inflammatory skin eruption (BLAISE). The overlapping features of lichen striatus and blaschkitis in our patient demonstrate the spectrum of clinical and pathologic features in patients with BLAISE.

Histopathological Study of a Broad Spectrum of Skin Dermatoses in Patients Affected or Highly Suspected of Infection by COVID-19 in the Northern Part of Italy: Analysis of the Many Faces of the Viral-Induced Skin Diseases in Previous and New Reported Cases

Skin manifestations of COVID-19 infections are diverse and are new to the dermatology community. We had the opportunity to examine the clinical and histopathological features of several patients who were divided into 3 groups. The first group included 8 COVID-19–positive patients who were hospitalized and quarantined at home. The second group included children and young adults who presented with chilblain erythema, erythema multiforme, and urticaria-like lesions. This group of patients was negative for the COVID-19 gene sequences by polymerase chain reaction but had a high risk of COVID-19 infection. The third group included clinically heterogeneous and challenging lesions. These patients were not subject to either polymerase chain reaction tests or serological analyses because they sought dermatological attention only for a dermatosis. The histopathological analysis of these cases showed a wide spectrum of histopathological patterns. What appears to be constant in all skin biopsies was the presence of prominent dilated blood vessels with a swollen endothelial layer, vessels engulfed with red blood cells, and perivascular infiltrates, consisting mainly of cytotoxic CD8+ lymphocytes and eosinophils. In 2 cases, there was diffuse coagulopathy in the cutaneous vascular plexus. In the early phases of the disease, there were numerous collections of Langerhans cells in the epidermis after being activated by the virus. The presence of urticarial lesions, chilblains, targetoid lesions (erythema multiforme–like lesions), exanthema, maculohemorrhagic rash, or chickenpox-like lesions associated with the histopathological features mentioned previously should cause clinical dermatologists to suspect the possibility of COVID-19 infection, especially in patients with fever and cough.

Plasmacytoid Dendritic Cells and Type I Interferon Signature in Lichen Striatus

BACKGROUND/OBJECTIVES

In addition to several infectious and neoplastic cutaneous entities, plasmacytoid dendritic cells (pDCs) have been shown to be involved in the pathogenesis of multiple cutaneous inflammatory and autoimmune disorders, including those characterized histologically by an "interface dermatitis" pattern such as lupus or lichen planus (LP), but their role in lichen striatus (LS), which is also known to have this histologic inflammatory pattern, has never been studied. The objective of the study was to investigate the role of pDCs in LS.

METHODS

Fifteen LS patients were found in our database and were immunohistochemically tested for pDC occurrence and activity using anti-blood-derived dendritic cell antigen-2 and anti-myxovirus resistance protein A (MxA) antibodies, respectively. These individuals were also compared with 15 individuals with LP.

RESULTS

pDCs were present in all individuals with LS and LP, but they were less abundant in those with LS, although MxA (surrogate marker of local type I interferon production and thus an indirect assessment of pDC activity) was similarly intense and diffuse in all individuals with LS and LP. In addition to being part of the upper dermal inflammatory bandlike infiltrate as in LP, LS cases, unlike LP, also showed perieccrine pDCs.

CONCLUSIONS

pDCs constitute a central component of the inflammatory infiltrate in LS, suggesting a significant role in its pathogenesis. pDC distribution (perieccrine distribution) could also help in microscopically differentiating LS from LP.