Interface dermatitis.

Interface dermatitis includes diseases in which the primary pathology involves the dermo-epidermal junction. The salient histological findings include basal cell vacuolization, apoptotic keratinocytes (colloid or Civatte bodies), and obscuring of the dermo-epidermal junction by inflammatory cells. Secondary changes of the epidermis and papillary dermis along with type, distribution and density of inflammatory cells are used for the differential diagnoses of the various diseases that exhibit interface changes. Lupus erythematosus, dermatomyositis, lichen planus, graft versus host disease, erythema multiforme, fixed drug eruptions, lichen striatus, and pityriasis lichenoides are considered major interface diseases. Several other diseases (inflammatory, infective, and neoplastic) may show interface changes.

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.

Generalized papular and sclerodermoid eruption: scleromyxedema.

Scleromyxedema (SM) is a rare chronic progressive and highly intractable cutaneous disease with unknown etiology, affecting both genders equally between 30 and 50 years. The disease is characterized with mucin deposits in the skin and/or other organs. In fact it is a clinicopathological subset of lichen myxedematosus (LM) according to a new classification. Sclerodermiform plaques and lichenoid papules are characteristic cutaneous lesions. An elevation of IgG λ (lambda) chain exists in most cases and extracutaneous involvement occurring with variable systemic findings is also detected. Generalized form is quite difficult to treat and may even be fatal. Herein, we present a male patient with typical features of generalized papular and sclerodermoid LM variety and with benign outcome by isotretinoin.

Lichen amyloidosus: a study of clinical, histopathologic and immunofluorescence findings in 30 cases.

BACKGROUND: Lichen amyloidosus (LA) is a primary localized cutaneous amyloidosis characterized clinically by discrete hyperkeratotic hyperpigmented papules and histologically by deposition of amyloid material in previously normal skin without any evidence of visceral involvement. AIMS AND OBJECTIVES: The aim of this work was to study the etiology, clinical features, histopathology and direct immunofluorescence findings in LA. METHODS: A prospective study of 30 patients with clinical, histological and immunofluorescence findings suggestive of LA was undertaken. After a detailed history and clinical examination, two punch biopsies for histopathology and immunofluorescence were taken. RESULTS: Of the 30 patients, 19 (63.3%) were males and 11 (36.7%) were females with duration of LA ranging from 6-20 months. Pruritus was the presenting symptom in 27 (90%) patients. Shin was involved in 26 (86.7%) followed by arms in three (10%) and back in one (3.3%). Seventeen patients (56%) had used scrubs for more than 2 years. Histopathology, direct immunofluorescence and Congo red staining detected amyloid in all cases. CONCLUSIONS: LA commonly presents over the shins as pruritic discrete hyperpigmented papules. Familial predisposition and friction may have a pathogenic role. Histopathological examination is very useful in the detection of amyloid which may be supplemented with direct immunofluorescence and Congo red staining.

Lichenoid and granulomatous dermatitis.

BACKGROUND: The prototypic lichenoid eruptions, lichen planus (LP), lichenoid drug eruptions, secondary syphilis, and collagen vascular disease, are defined histologically by a band-like lymphocytic infiltrate in close apposition to the epidermis. We describe a novel form of lichenoid dermatitis with a granulomatous component. DESIGN: Skin biopsies from 40 patients demonstrating a band-like lymphocytic infiltrate with concomitant granulomatous inflammation were encountered over 4 years. Clinicians were contacted to elucidate underlying triggers and medical illnesses. RESULTS: A lichenoid dermatitis, a linear eruption, vasculitis, annular erythema, and erythroderma were among the clinical presentations. A drug-based etiology was implicated in 14 cases: the drugs included antibiotics, lipid-lowering agents, anti-inflammatory drugs, antihistamines, hydroxychloroquine sulfate, and angiotensin-converting enzyme inhibitors. Over one-third of patients with drug-related eruptions had other medical illnesses associated with cutaneous granulomatous inflammation, namely rheumatoid arthritis (RA), Crohn's disease, hepatitis C, diabetes mellitus, and thyroiditis. A microbial trigger was implicated in 12 patients in the context of infective id reactions to herpes zoster, Epstein-Barr virus (EBV), or streptococci, or active infections by Mycobacterium tuberculosis, M. leprae, fungi, and spirochetes. The remainder had hepatobiliary disease and RA without obvious exogenous triggers, cutaneous T-cell lymphoma (CTCL), and idiopathic lichenoid eruptions (i.e. LP, lichen nitidus, and lichen striatus). One patient with LP had underlying multicentric reticulohistiocytosis. The histiocytic infiltrate assumed one or more of five light microscopic patterns: (i) superficially disposed loose histiocytic aggregates; (ii) cohesive granulomata within zones of band-like lymphocytic infiltration with or without deeper dermal extension; (iii) a diffuse interstitial pattern; (iv) scattered singly disposed giant cells; and (v) granulomatous vasculitis. Additional features included lymphocytic eccrine hidradenitis in those patients with drug reactions, hepatobiliary disease, and antecedent viral illnesses, tissue eosinophilia and erythrocyte extravasation in drug hypersensitivity, granulomatous vasculitis in patients with microbial triggers, drug hypersensitivity or RA, and lymphoid atypia in lesions of CTCL or drug hypersensitivity. CONCLUSIONS: The cutaneous lichenoid and granulomatous reaction may reflect hepatobiliary disease, endocrinopathy, RA, Crohn's disease, infection, or a drug reaction. One-fifth of cases represent idiopathic lichenoid disorders. Lymphoproliferative disease or pseudolymphomatous drug reactions must be considered in those cases showing lymphoid atypia.