Pityriasis lichenoides et varioliformis acuta and acquired toxoplasmosis

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.

Febrile ulceronecrotic Mucha-Habermann disease

The Mucha-Habermann disease is an inflammatory disease of the skin and is a variant of pityriasis lichenoides et varioliformis acuta. We describe the case of a 64-years-old woman who was admitted for erysipelas of the face. Despite treatment, evolution was marked by the appearance of a necrotising ulcerative area in the centre of the erysipelas associated with local oedema and headache. A skin biopsy revealed a pityriasis lichenoides et varioliformis acuta. Corticosteroids led to a rapid stabilisation of lesions, and after 6 months the patient shows only a small area of frontal hypopigmentation. The aetiology remains uncertain. There is no established standard treatment. We would like to draw attention of the medical and surgical specialists to this rare disease. The diagnosis should be considered in a necrotic lesion associated with rapid expansion of systemic and peripheral cutaneous signs. Diagnosis must be considered to avoid unnecessary debridement and extensive scars.

Pityriasis lichenoides and its subtypes

Pityriasis lichenoides represents a unique group of inflammatory skin disorders that include pityriasis lichenoides et varioliformis acuta (PLEVA), febrile ulceronecrotic Mucha-Habermann disease (a subtype of PLEVA), and pityriasis lichenoides chronica. The history, epidemiology, clinical features, pathophysiology, and treatment of this group of conditions are reviewed in this manuscript.

Infectious causes of pityriasis lichenoides: a case of fulminant infectious mononucleosis

Pityriasis lichenoides is a rare cutaneous eruption of unknown cause that spans a spectrum of clinical severity. Infectious agents have long been suspected as etiologic factors. The present case is the first to demonstrate a known EBV-mediated process evolving and resolving in concert with pityriasis lichenoides. Epstein-Barr virus, Toxoplasma gondii, and HIV are the most frequently reported infectious triggers of pityriasis lichenoides. Pityriasis lichenoides may arise secondary to EBV-mediated acute infectious mononucleosis.

Pityriasis lichenoides in children: a long-term follow-up of eighty-nine cases

Pityriasis lichenoides is usually classified into an acute and a chronic form. From a review of 89 cases of the disease seen since 1974 it seems that a more realistic classification into three main groups, according to the distribution of pityriasis lichenoides lesions, could be made, namely, a diffuse, a central, and a peripheral form, each characterized by a different clinical course. Conversely, no correlations were detected in our series between the severity of skin lesions and their distribution or the overall course of the disease. None of our cases suggests the possible evolution of pityriasis lichenoides into lymphomatoid papulosis. Although no infectious causative agent has been identified, a viral origin seems likely in some cases. Most patients responded favorably to UVB irradiation. Our conclusions are (1) that pityriasis lichenoides is probably a clinical disorder with a diverse etiology and (2) that its classification by distribution seems more useful than its subdivision into an acute and a chronic form.