Lichen striatus. Histological, immunohistochemical, and ultrastructural study of 37 cases

Post-Inflammatory Hypopigmentation: Review of the Etiology, Clinical Manifestations, and Treatment Options

Post-inflammatory hypopigmentation is a common acquired pigmentary disorder that is more prominent in skin of color, leading to great cosmetic and psychosocial implications. Often, a diagnosis with a pigmentary disorder can negatively impact an individual's health-related quality of life and may result in stigma. Although most cases of post-inflammatory hypopigmentation resolve spontaneously over time, a systematic diagnostic approach can help with identifying the underlying etiology and informing treatment strategies. It can be due to cutaneous inflammation, sequelae of inflammatory or infectious dermatoses, or dermatologic procedures. Therefore, a thorough understanding of the epidemiology, patient history, physical exam findings, and clinical features of post-inflammatory hypopigmentation phenomenon can explain the primary cause to providers and allow for patient education. It is also important to understand the various therapeutic approaches available and the efficacy of these options, which will inform providers to choose the appropriate therapy for patients. Although algorithms exist for classifying acquired disorders of hypopigmentation, there are no established algorithms for the diagnosis and treatment of post-inflammatory hypopigmentation, which warrants further exploration and discourse.

Cutaneous eccrine inflammation and necrosis: review of inflammatory disorders affecting the eccrine apparatus including new associations

Despite being frequently overlooked during the examination of histopathological sections, eccrine sweat glands can offer clues for diagnosing various skin conditions. They provide important functions and can lead to several diseases when inflamed or injured. This review article provides information regarding eccrine physiology as well as well-established and novel entities that occur in association with eccrine gland pathology.

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.

Adnexotropic Variants of the Interface Dermatitides: A Review

The interface dermatitides encompass a vast array of cutaneous entities which, at times, may present with particular clinical variants with adnexal predilection. Similarly, hair follicle and eccrine gland involvement of some of these entities has been observed on histopathology. This review aims to describe the various adnexotropic presentations of the interface dermatitides. Recognizing that the adnexa can be a frequent site of involvement of these conditions may aid dermatopathologists in making the correct diagnosis and avoid misinterpreting adnexotropism for other conditions such as the great imitator, mycosis fungoides.

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.

Pityriasis Lichenoides: A Large Histopathological Case Series With a Focus on Adnexotropism

INTRODUCTION

Pityriasis lichenoides (PL) is an infrequent skin disorder. The clinical manifestations are usually specific enough for a reliable diagnosis, although the histopathological assessment of a biopsy is sometimes needed to differentiate between PL and a range of other diseases. The objectives of this study were to review cases of PL managed in our hospital, confirm the classical histopathological features of PL, and identify signs that may be of value in the diagnosis of PL.

MATERIALS AND METHODS

All cases of PL assessed in our pathology department between January 2007 and December 2017 were retrieved, and all slides were reviewed. Cases were selected only if a diagnosis of PL was initially suggested by a dermatologist and then confirmed by the histopathological assessment.

RESULTS

Seventy-one cases met the study criteria. The following features were almost always present: vacuolar changes or necrotic keratinocytes (100%), both superficial and deep lymphocytic infiltrates (99%), and the infiltration of lymphocytes into the adnexal epithelium (97%). The inflammatory cells were always small- to medium-sized lymphocytes. There were no eosinophilic infiltrates. Superficial perivascular and/or intraepidermal red blood cells were observed in 83% of cases.

DISCUSSION

We highlighted the presence of a deep dermal lymphocytic infiltrate, with a "T-shaped" periadnexal arrangement along the full length of the follicular and sudoral epithelia. This might be a feature that enables the differentiation of PL from other diseases. Our findings also prompted a number of physiopathological hypotheses for PL.

CONCLUSIONS

Our present results confirmed the classical histological aspects of PL and provided some useful new diagnostic features.

Mosaicism in genodermatoses

Genodermatoses are inherited disorders presenting with cutaneous manifestations with or without the involvement of other systems. The majority of these disorders, particularly in cases that present with a cutaneous patterning, may be explained in the context of genetic mosaicism. Despite the barriers to the genetic analysis of mosaic disorders, next-generation sequencing has led to a substantial progress in understanding their pathogenesis, which has significant implications for the clinical management and genetic counseling. Advances in paired and deep sequencing technologies in particular have made the study of mosaic disorders more feasible. In this review, we provide an overview of genetic mosaicism as well as mosaic cutaneous disorders and the techniques required to study them.

The color of skin: white diseases of the skin, nails, and mucosa

White diseases are a heterogenous group characterized by hypopigmentation or depigmentation. Skin and eye color are determined by the number and size of melanosomes present. Melanin is produced by melanosomes in the melanocytes present within the epidermis of the skin, uvea, and retinal pigmented epithelium (RPE). Conditions altering the number of melanocytes or concentration of melanin result in a lack of pigmentation, appearing as "white diseases" ranging from the well-known albinism and vitiligo to more esoteric white hand syndrome and Degos disease.

Lichen planus and lichenoid dermatoses: Clinical overview and molecular basis

Deriving from the Greek word λειχήν for "tree moss" and the Latin word planus for "planar," lichen planus is a relatively uncommon and heterogeneous cutaneous disorder that typically develops in middle-aged adults. Despite the significant clinical burden associated with the disorder, little well-conducted molecular research has been undertaken, possibly because of heterogeneity impeding consistent and confident phenotyping. The multiple variants of lichenoid disease bear overlapping clinical and pathologic features despite manifesting as distinct clinical disorders. The first article in this 2-part continuing medical education series provides a comprehensive overview of the clinical and pathologic characteristics of cutaneous lichenoid dermatoses and links these manifestations to recent advances in our understanding of the underlying pathobiology of such diseases.

Asymmetric Bilateral Lichen Striatus: A Rare Presentation following Multiple Blaschko's Lines

Lichen striatus (LS) is an uncommon, acquired, self-limited, and benign linear dermatosis of unknown etiology that most often occurs unilaterally and is confined to the lines of Blaschko. A healthy 7-year-old girl presented to our clinic with bilateral asymmetric LS occurring on the right arm and left leg of 1-year duration. Very few cases of bilateral LS have been previously reported in the literature, with none from clinics within the United States. The etiology of LS is currently unknown; however its confinement to Blaschko's lines, which represent embryologic migration of skin cell clones, does provide insight into a possible pathogenesis. It seems most likely that an individual's development of LS is linked to their genetic predisposition and a subsequent triggering event. Our case serves as a strong example of a rare presentation of LS and facilitates discussion of the clinical diagnostic process and possible pathogenesis of this dermatosis.

[Skin biopsy of inflammatory skin diseases in childhood-when is it reasonable?]

Compared with adulthood, inflammatory skin diseases are relatively rarely biopsied in children. Apart from the invasiveness of the procedure, the required local anesthesia, and the risks of infection and scarring, the psychological trauma of the operation has a higher impact in childhood. If a biopsy is performed, expectations towards the dermatopathology report are high. However, the evaluation of biopsies taken from children is challenging for the dermatopathologist: on the one hand, because the biopsies are often tiny or just superficial shaves and, on the other hand, because criteria for evaluation have mostly been developed from findings in adult biopsy specimens. In children, the immune system is still in the process of maturation and, therefore, infiltrates in the skin may look different from those seen in adults; however, knowledge about that is very limited to date. Moreover, numerous rare genodermatoses may manifest themselves first in childhood and need to be considered in the differential diagnosis while experience with them is often limited. Starting from the clinical presentation, this article presents histopathological features of possible differential diagnoses in order to demonstrate the value or necessity of a skin biopsy in a pediatric patient. In addition, communication with parents and child, methods of local anesthesia and biopsy techniques will be considered.

Histopathology of Cutaneous Inflammatory Disorders in Children

Inflammatory dermatoses encompass a variety of histologic patterns that affect different portions of the skin. In spongiotic, psoriasiform, lichenoid, pityriasiform, and blistering disorders, there are predominately epidermal and junctional activities with variable superficial dermal inflammation. Hypersensitivity reactions can show either epidermal or mostly dermal changes depending on whether the exposure of the exogenous allergen occurs through an external or internal route, respectively. Exceptions include erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis, where the etiology is often due to infection or ingested medications, but the histologic features are almost exclusively confined to the epidermis and dermoepidermal junction. Autoimmune disorders are unique in that lesions typically incorporate a mixture of epidermal and dermal inflammatory patterns with periadnexal inflammation, while the vast majority of vasculitis/vasculopathy and alopecia have changes limited to only the vessels and hair follicles, respectively. It is critical to recognize that a relatively limited number of histologic patterns are seen in a large array of clinical entities. Therefore, clinicopathologic correlation and careful examination of histologic details are of the utmost importance when evaluating skin biopsies for inflammatory disorders.

Lichen striatus successfully treated with oral cyclosporine

Lichen striatus is an acquired, benign, linear inflammatory dermatosis characterized by a sudden skin eruption along Blaschko's lines that usually is not associated with specific etiologic agents. In most cases, it is a self-limited dermatosis, but may relapse. Topical steroids are its first-line therapy, but this treatment is not always effective. We describe the case of a 45-year-old woman affected by a lichen striatus on her right limb resistant to topical corticosteroid therapy. The patient was successfully treated with cyclosporine (4 mg/kg/die) for 4 weeks with no recurrence of the dermatitis during the subsequent 1-year follow-up period.

Lichenoid and interface dermatoses

The terms 'lichenoid' and 'interface' dermatitis are often used interchangeably to describe an inflammatory pattern characterized histologically by damage to the basal keratinocytes in the epidermis. The mechanism of cell damage of such cells is now best understood as apoptosis, or programmed cell death. This inflammatory pattern of dermatoses, is also accompanied frequently by a band of lymphocytes and histiocytes in the superficial dermis, that often obscures the dermal-epidermal junction, hence the term 'lichenoid'. A discussion of the more common lichenoid/interface dermatitides encountered in the routine clinical practice encompasses the following entities: lichen planus, lupus erythematosus, dermatomyositis, erythema multiforme, graft versus host disease, fixed drug reactions, and multiple others.

Lichen striatus with syringotropism and hyperplasia of eccrine gland cells: a rare phenomenon that should not be confused with syringotropic mycosis fungoides

BACKGROUND

Syringotropism is characterized by lymphocyte infiltration in the eccrine gland and is usually associated with various degrees of hyperplasia of eccrine gland cells. This phenomenon has been reported in rare cases of mycosis fungoides, which are also called as syringotropic mycosis fungoides.

METHODS

We studied seven cases of lichen striatus associated with syringotropism and hyperplasia of eccrine gland cells, diagnosed at our dermatology department in the past 5 years. The hematoxylin and eosin-stained slides from these cases were analyzed, and immunohistochemical and T-cell receptor gene rearrangement studies were performed.

RESULTS

Of the seven cases, two showed prominent and five showed subtle syringotropism and hyperplasia of eccrine gland cells. Immunohistochemical study showed mixed infiltration by T-cells and B-cells around the eccrine glands. The T-cells were composed of CD4 and CD8-positive cells. T-cell receptor gene rearrangement study showed negative results in all the cases.

CONCLUSION

Syringotropism and hyperplasia of eccrine gland cells is a rare phenomenon in lichen striatus. Dermatopathologists should be aware of this to avoid misdiagnosis as syringotropic mycosis fungoides.

Clinicopathological Study of Non-Infectious Erythaematous Papulosquamous Skin Diseases

INTRODUCTION

Papulosquamous diseases are characterized by scaly papules and plaques with similar clinical picture which amounts to confusion and hence, a definitive histopathological diagnosis goes a long way in treatment of such diseases.

AIM

The aim of the study was to study the histomorphology of non-infectious, erythaematous, papulosquamous lesions of skin with clinicopathological correlation.

MATERIALS AND METHODS

Skin biopsies from 150 clinically diagnosed/suspected non-infectious erythaematous, papulosquamous skin diseases were received in the Department of Pathology. The specimens obtained were subjected to formalin fixation and paraffin embedding, stained with haematoxylin and eosin and studied. The lesions were classified as psoriasis, lichen planus, lichen nitidus, lichen striatus, pityriasis rosea and pityriasis rubra pilaris and clinicopathological correlation was done.

RESULTS

Papulosquamous lesions were common in the elderly. Males were commonly affected except in pityriasis rosea. Among the 150 cases studied, 72 cases (48%) were histopathologically confirmed to be papulosquamous lesions. Psoriasis was the most common lesion.

CONCLUSION

Key histopathological features and clinicopathological correlation gives a conclusive diagnosis. The importance of specific histomorphological diagnosis lies in distinguishing these lesions as the treatment and prognosis varies widely.

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.

Lichen striatus versus linear lichen planus: a comparison of clinicopathological features, immunoprofile of infiltrated cells, and epidermal proliferation and differentiation

BACKGROUND

Lichen striatus (LS) and linear lichen planus (LLP) are separate uncommon disorders belonging to linear inflammatory dermatoses. The immunotyping of inflammatory cells has been investigated in LS and lichen planus (LP), but epidermal proliferation and differentiation have little been described in LS and LLP.

METHODS

The clinical and pathological data of eight patients with LS and seven with LLP were retrospectively collected. Immunotyping of infiltrated cells and expression of Ki-67, K16, involucrin, and filaggrin were stained by immunohistochemistry in skin lesions of these patients and normal skin of eight healthy controls.

RESULTS

Dermal infiltrates contained primarily CD3+ and CD68+ cells in three groups. CD4+ cells were predominantly located in the perivascular area, while CD8+ cells were frequently close to the junctional zone. Compared with control skin, epidermal and dermal CD1a+ cells, and dermal CD3+, CD4+, CD8+, and CD68+ cells were increased in LS and LLP (P < 0.05), while Ki-67+ cells were significantly high in LLP (P < 0.05) but not in LS. K16 and involucrin expression in LLP were more extensive than in LS, and filaggrin expression was similar between both entities.

CONCLUSIONS

Our results indicate that the predominance of CD8+ cells and increased epidermal proliferation and abnormal keratinization are present in both dermatoses, although the levels of the above indexes are mild in LS as compared to LLP. These two entities might be due to the interaction of infiltrated cells and keratinocytes, and CD8+ cells could play a pivotal role in their pathogenesis.

Differential Diagnosis of Linear Eruptions in Children

A 3-year-old girl presented with a linear eruption on her leg for 2 months. She was otherwise healthy and well-appearing. Physical examination showed many small, erythematous, flat-topped papules coalescing into a linear erythematous plaque. At a follow-up visit 9 months later, the eruption had resolved, leaving postinflammatory hypopigmentation.When approaching a cutaneous eruption, appreciating the pattern of the lesions can be instrumental to arriving at the correct diagnosis. For this patient with the acute onset of a plaque on the leg, the differential diagnosis is narrowed by the linear distribution of the skin lesions. The differential diagnosis of linear eruptions in children includes lichen striatus, linear lichen planus, linear psoriasis, inflammatory linear verrucous epidermal nevus, incontinentia pigmenti, phytophotodermatitis, and allergic contact dermatitis. Of note, many of these conditions manifest in a linear manner as a result of cutaneous mosaicism, whereas others are caused by external agents contacting the skin.

Granulomatous disorders

Almost all granulomatous skin disorders can cause red lesions on the face. Such disorders may include many bacterial, fungal, or parasitic infections, noninfectious inflammatory disorders, foreign body reactions, and even neoplasms. Clinically, they usually present with papules, plaques, nodules, and/or abscesses, which may ulcerate. It may be helpful in their differential diagnosis to define certain clinical patterns, such as multiple and discrete papules, necrotic or umbilicated papules or nodules, annular plaques, vegetative plaques or tumors, verrucous plaques or tumors, abscesses and/or sinuses, and lymphocutaneous pattern. Some disorders, such as sarcoidosis, can cause a wide variety of lesions. We accept that cutaneous leishmaniasis is also among such great imitators.

Facial lichen striatus in children: retracing the lines of Blaschko

We report seven patients with facial lichen striatus along the lines of Blaschko who presented to our pediatric dermatology unit between 2003 and 2009. The mean age of diagnosis was 4.6 years (range 2.5-9 years). Three of the cases were associated with atopic dermatitis, and one case presented with vitiligo. In the six patients for whom we have follow-up, all lesions resolved without pigmentary changes in an average of 11 months. This case series describes the distribution, presentation, and natural history of lichen striatus along facial lines of Blaschko. From our experience, clinical diagnosis and monitoring without biopsy is a reasonable approach to the management of uncomplicated lichen striatus, particularly when the face is involved.

Lichen striatus on adult

Lichen Striatus is an uncommon inflammatory skin eruption of unknown etiology. It rarely affects adults, and it is characterized by abrupt onset of coalescent papules, in a linear disposition, usually on the extremities. Histopathology shows lichenoid reaction involving follicles and glands. Occasionally, there is overlap with linear lichen planus and "blaschkitis", the main differential diagnoses. It is reported here the case of an adult woman with erythematous violaceous papules on the right side of the neck and face, diagnosed with lichen striatus by clinical and histopathological correlation. The atypical findings and the diagnostic difficulty are discussed.

Simultaneous lichen striatus in siblings along the same Blaschko line

Lichen striatus (LS) is an asymptomatic, spontaneously resolving linear dermatosis consisting of 2 to 4 mm flat topped papules following the lines of Blaschko. Two siblings presented with a simultaneous occurrence of LS along the same Blaschko line of the left upper extremity. Only four other cases of a simultaneous occurrence of LS in related siblings have been reported, but none of these have occurred in the same extremity. Although 10 years have passed since the last case report of this unique concurrent familial eruption, few discoveries have been made regarding its etiology. Several theories have been proposed including environmental agents, cutaneous injury, viral infection, hypersensitivity, and genetic predisposition. These theories are discussed along with retrotransposons, a possible new explanation for the pathogenesis of this and other Blaschko line disorders.

Lichen striatus in adults and pimecrolimus: open, off-label clinical study

BACKGROUND

Lichen striatus is a well-known, acquired, self-healing, linear inflammatory dermatosis. Lichen striatus occurring in adults tends to be more extensive and itchy than in children, sometimes requiring symptomatic treatment. The therapeutic approach usually adopted is topical steroids, even though prolonged use may lead to several side-effects, particularly cutaneous atrophy.

OBJECTIVE

To report the results of an open, off-label study on the use of pimecrolimus 1% in the treatment of diffuse, nonresponsive forms of lichen striatus.

METHODS

Three adult patients suffering from relapsing or disseminated and itchy lichen striatus received topical application of pimecrolimus 1% cream (Elidel, Novartis Pharma, Basle, Switzerland) twice daily for 6 weeks, or until complete disappearance of the cutaneous lesions.

RESULTS

All patients experienced rapid healing of the dermatosis, without any recurrence for at least 14 months.

CONCLUSION

Our preliminary results show that pimecrolimus may represent a useful therapeutic alternative for lichen striatus, although further studies on a larger number of cases are needed to confirm its safety and efficacy in the treatment of this condition.

"Pediatric blaschkitis": expanding the spectrum of childhood acquired Blaschko-linear dermatoses

We describe two young children who developed relapsing, pruritic, papulovesicular eruptions in multiple bands along Blaschko lines on the neck, trunk, and extremities. Skin specimens in both revealed spongiotic dermatitis. This represents the first report of "blaschkitis" in children, providing further evidence that lichen striatus and blaschkitis are related acquired Blaschko-linear dermatoses that exist on a spectrum rather than as the childhood and adult form of a single disease entity. We highlight the features that differentiate blaschkitis from lichen striatus, review the potential roles of cutaneous mosaicism, environmental triggers, and background immunologic state in their pathogenesis, and discuss the spectrum of inflammatory dermatoses that can follow Blaschko lines.

Lichen striatus in a pregnant woman

We report a case of lichen striatus in a 37-year-old woman in the third trimester of pregnancy. She presented at 35 weeks of pregnancy with a 6-week history of a pruritic rash on the left side of her abdomen. Examination revealed an erythematous papular eruption arranged in a linear fashion from the umbilicus to the left mid back. Histological examination demonstrated lichenoid perivascular and periadnexal inflammatory infiltrate and the presence of colloid bodies. The eruption resolved prior to delivery with the application of mometasone furoate 0.1% ointment.

Lichen striatus: clinical and laboratory features of 115 children

To analyze the clinical features, response to treatment, and follow-up of lichen striatus and any associated symptoms or disease, we designed a retrospective study involving 115 affected children at the Pediatric Dermatology Unit of the Department of Dermatology of the University of Bologna, Bologna, Italy. Between January 1989 and January 2000 we diagnosed lichen striatus in 37 boys and 78 girls (mean age 4 years 5 months). We studied their family history and the season of onset, morphology, distribution, extent, duration, histopathology, and treatment of their lichen striatus. We found that family history was negative in all our patients except for two pairs of siblings. The majority of children had the disease in the cold seasons; precipitating factors were found in only five cases. The most frequently involved sites were the limbs, with no substantial difference between upper and lower limb involvement. When lichen striatus was located on the trunk and face, it always followed Blaschko lines; in seven children the bands on the limbs appeared to be along the axial lines of Sherrington. In 70 cases, lichen striatus was associated with atopy. The mean duration of the disease was 6 months and relapses were observed in five children, and in one instance the disease had a prolonged course. Only a few case study series of lichen striatus in children have been reported and ours is the largest to date. The etiology of lichen striatus remains unknown in the majority of our patients. The confirmed association with atopy observed in our patients may be a predisposing factor. It has generally been accepted that lichen striatus follows the lines of Blaschko, and this distribution is a sign of both a topographic and a pathogenetic concept. In patients where lichen striatus is along axial lines, a locus minoris resistentiae, we suppose that this distribution may only be an illusory phenomenon in instances in which the trigger factor prefers this route, consisting of several successive Blaschko lines, but appearing as a single band.

Lichen striatus in adults or 'adult blaschkitis'? There is no need for a new naming

BACKGROUND

Lichen striatus (LS) is a well-known acquired linear inflammatory dermatosis. In 1990, Grosshans and Marot introduced the term 'adult blaschkitis' (AB), describing an eruption similar to LS occurring in an adult (adult LS). Does there really exist a new entity or a need for a new naming?

OBJECTIVE AND METHODS

Two new cases of adult LS are described and the data from 16 earlier cases (12 AB and 4 adult LS) are reviewed.

RESULTS

The analysis of 18 adult patients with an acquired inflammatory blaschkolinear eruption reveals that females are affected two times as frequently as males. The mean age at onset is 44 years, the mean duration until spontaneous cure 8.7 months. Relapses occur in 27.7%. In 78%, the eruption is localized on the trunk, in 55% on the arms and in 50% on the legs. Multilinearity is found in 100% if the eruption is on the trunk, and 61.5% if it is on the limbs. Neither clinical nor morphological differences exist between AB and adult LS.

CONCLUSION

There are no convincing characteristics which justify creating a new name or even a new entity. AB may be the same as LS, a well-known acquired linear inflammatory dermatosis, which--as has been shown now--does not occur so rarely in adults. However, the etiology of this entity remains obscure.

Facial lichen striatus: successful treatment with tacrolimus ointment

We report a 22-year-old Japanese woman with facial lichen striatus (LS). The distribution of the lesions corresponded to that of Blaschko's lines. Histology of the lesional skin showed an inflammatory cell infiltrate around hair follicles and eccrine glands. Treatment of the linear lesions with tacrolimus ointment once or twice daily resulted in a dramatical improvement in a short time. LS is a T-cell-mediated inflammatory disease and tacrolimus ointment may be an effective alternative treatment for this disease especially when the lesions are located on the face.

Periappendageal lichen nitidus: report of a case

BACKGROUND

The histology of lichen nitidus has been described previously but a follicular variant has not been emphasized.

METHOD

We report a case of lichen nitidus with periappendageal inflammation resulting in histologic similarities to lichen striatus.

RESULTS

This case extends the spectrum of histologic findings in lichen nitidus and shows overlap in the distribution of the inflammatory infiltrate in lichen nitidus and lichen striatus.