Distinguishing Features: Linear Rashing is Not Always Koebnerization

Cutaneous sarcoidosis and psoriasis are dermatologic conditions that can have a similar clinical appearance. Psoriasiform sarcoidosis shows thick white or silvery scaling reminiscent of psoriasis and both conditions can be linear. Psoriasis is associated with linear scaled patches that are induced by mechanical trauma (Koebner Phenomenon). Linear lesions in cutaneous sarcoidosis are not a result of koebnerization, rather cutaneous granulomas appear in well-healed scars decades after the trauma within what can be termed an immunocompromised district. This paper will focus on the features that distinguish psoriasis and cutaneous sarcoidosis, since prompt diagnosis leads to appropriately targeted treatment.

Generalized ILVEN or Blaschkoid Psoriasis: A Persistant Dilemma

A 24-year-old man presented with itchy verrucous, scaly red-brown papules, & linear plaques distributed in a blaschkoid pattern all over the body since last 20 years associated with itching. A skin biopsy was consistent with ILVEN (inflammatory linear verrucous epidermal nevus). Histopathologically, it can be difficult to distinguish it from linear psoriasis. It may respond to conventional anti-psoriatic therapies like potent topical corticosteroids applied under occlusion, or systemic treatments like acitretin.

Widely Spread Unilateral Inflammatory Linear Verrucous Epidermal Nevus (ILVEN)

Inflammatory linear verrucous epidermal nevus (ILVEN) is an epidermal nevus that clinically and histologically mimics linear psoriasis. The pathogenesis of psoriasis has been widely investigated, with recent studies focusing especially on targeting proinflammatory cytokines such as IL-17A, TNFα, IL-23, and IL-12, while little is known about ILVEN. Since the treatment for ILVEN varies widely from the administration of topical ointment for psoriasis to invasive methods such as carbon dioxide gas laser, the differential diagnosis between ILVEN and psoriasis is necessary. In this report, we describe a case of widely spread unilateral ILVEN that clinically and histologically mimicked psoriasis vulgaris and could be diagnosed by immunohistochemical staining focused on the IL-36γ/IL-17A axis.

Study on linear dermatoses

<p class="abstract"><strong>Background:</strong> The objective of the study was to study the incidence, age and sex distribution, association, distribution, clinical presentation, histopathological correlation of linear dermatoses at the skin Outpatient Department.</p><p class="abstract"><strong>Methods:</strong> A prospective study was conducted over a period of 1 year in 90 patients, attending the Department of Dermatology, at a tertiary care hospital, Chennai. Data collection, clinical examination and skin biopsy were recorded and analyzed statistically. Inclusion criteria were all patient with linear dermatoses. Exclusion criteria were Koebner phenomenon.<strong></strong></p><p class="abstract"><strong>Results:</strong> The incidence of linear dermatoses in our outpatient department- 0.2% per year. Among the linear dermatoses, lichen striatus was found to be the most common. The other dermatoses following Blaschko’s lines, in the descending order of frequency seen in this study were linear epidermal nevus, linear lichen planus, linear morphoea, inflammatory linear verrucous epidermal nevus, segmental vitiligo, hypomelanosis of ito, linear lichenoid dermatitis, linear psoriasis, segmental neurofibromatosis, linear whorled nevoid hypermelanosis, incontinentia pigmenti, nevus depigmentosus, linear porokeratosis. Female preponderance was noted. Majority of patients showed unilateral distribution mostly on the extremities.</p><p class="abstract"><strong>Conclusions:</strong> Most of the linear lesions are arranged along Blaschko’s line. The importance of histopathological correlation is obvious. Cases which were clinically diagnosed as lichen striatus, showed histopathological features of psoriasis and linear epidermal verrucous nevus. One case diagnosed clinically as epidermal nevus was found to be super imposed by psoriasis histologically. Another case clinically diagnosed as linear psoriasis clinically, was found to be linear porokeratosis on histopathology. Very few associations were noted.</p>