Lichenoid tissue reaction/interface dermatitis: Recognition, classification, etiology, and clinicopathological overtones.

Lichenoid tissue reaction or interface dermatitis embrace several clinical conditions, the prototype of which is lichen planus and its variants, drug induced lichenoid dermatitis, special forms of lichenoid dermatitis, lichenoid dermatitis in lupus erythematosus, and miscellaneous disorders showing lichenoid dermatitis, the salient clinical and histological features of which are described to facilitate their diagnosis. Background of lichenoid reaction pattern has been briefly outlined to enlighten those interested in this entity.

Adult onset pityriasis rubra pilaris.

Pityriasis rubra pilaris (PRP) has always been an intriguing topic ever since its inception. It is a group of chronic disorders characterized by reddish orange plaques with pityriasiform scaling showing follicular keratoses, palmoplantar keratoderma, and sometimes, erythroderma. It occurs all over the world but with racial variations. Its incidence might vary and the age at onset, behavior, clinical appearance, and prognosis are considered to be very important for its classification. It may manifest either as Type I classical adult onset PRP, Type II atypical adult (onset) PRP, or Type VI PRP (HIV-associated PRP pityriasis rubra pilaris) in contrast to classical juvenile (Type III) and circumscribed juvenile (Type IV) encountered among children. Its diagnosis is largely clinical with microscopic pathology being a useful supplement, but it continues to be a therapeutic dilemma. We review the epidemiology of adult onset PRP here and take stock of the prevalent treatment options.

Psoriasiform dermatoses.

Psoriasiform reaction pattern is a commonly encountered denominator in a wide variety of unrelated disorders. It may be a reaction to either the internal or the external environmental, allergic, infective, parasitic, bacterial, fungal, viral and/or malignant stimuli. The degree of evolution of such a pattern and its significance vary according to the dermatosis. The age of the skin lesions may also influence the histopathological presentation and its clinico-histopathological disparity can often bewilder an expert. However, such a situation warrants more astute and sustained observations to unveil the exact underlying condition(s). Thus, psoriasiform dermatoses should only be an initial caption until an exact dermatological disorder is defined. There has been greater number of instances of psoriasiform drug eruptions where a confirmation of the diagnosis can be achieved after their remission by doing a provocation test. Similarly, such instances have also been on the rise in HIV/AIDS-affected individuals all over the world. Besides mycosis fungoides and Hodgkin's disease, several unrelated malignancies have been preceded or accompanied by psoriasiform skin eruptions.

Vitiligo: compendium of clinico-epidemiological features.

Vitiligo, an autoimmune disorder characterized by localized and/or generalized depigmentation of the skin and/or mucous membranes, is a well-recognized entity. The imperatives of its epidemiology both in rural India and in global reckoning have been highlighted frequently. Its morphology is striking and is characterized by asymptomatic ivory/chalky white macule(s) that may be frequently surrounded by a prominent pigmented border, the 'trichrome vitiligo'. However vitiligo may have morphological variations in the form of: trichrome, quadri-chrome, penta-chrome, blue and inflammatory vitiligo. Its current topographical classification into segmental, zosteriform and nonsegmental, areata, vulgaris, acrofacialis and mucosal represent its well acclaimed presentations. Its adult and childhood onset is well appreciated as also its presentation in males and females. Occasionally, it may be possible to identify triggering factors. Vitiligo may be associated with cutaneous, ocular and systemic disorders, the details of which are discussed in this article.