Introduction: Histoid Hansen is rare but a well-defined entity with specific clinical, histopathological, and bacteriological features. The incidence has been reported to vary from 1-2% amongst total leprosy patients. Methodology:  We performed a retrospective analysis of the records of patients identified as histoid Hansen on the basis of clinico-histopathological criteria, who attended the Hansen clinic from 2000-2009. Results: A total of 962 leprosy patients attended the Hansen clinic from 2000-2009, and of these, 11 (1.14%) were diagnosed as histoid Hansen. The youngest patient on record was 14 years of age. Nearly 70% of the patients were untreated and the rest were on multidrug therapy (MDT) before development of histoid lesions. Three patients showed Erythema nodusum leposum (ENL) reaction. Conclusion: India has achieved elimination of leprosy, but new cases of histoid are still recorded with the same incidence rate. Reactions are not uncommon in such forms, and may be a transition phase to manifest lepromatous leprosy. A thorough knowledge and early detection is needed for this uncommon variant of leprosy which can pose a threat to our elimination drive.

The histopathological features of skin tissue sections in patients clinically diagnosed as leprosy were correlated with the histopathological features of nerve specimens obtained from the same patients. Fifty untreated leprosy patients attending the Outpatient Department of the Department of Dermatology and Sexually Transmitted Diseases of Smt. Sucheta Kriplani and Kalawati Saran Children's Hospitals, New Delhi, India were included in the study. On correlating the histological features of skin and nerve tissue sections, concordant findings were found in 24 out of the 50 patients (48%) but discordance between the histopathological features of skin and nerve tissue sections were found in 26 out of 50 cases (52%). Of these 26 cases, the nerve tissue histology when compared with the skin histology showed features lower down the disease spectrum in 17 (34%) cases. Seven of the 50 patients (14%) showed histological features of leprosy higher in the disease spectrum in the nerve tissue sections than in the skin biopsy sections. One patient clinically LL leprosy demonstrated histopathological features of Histoid leprosy in the skin sections and LL in the nerve sections. The remaining one patient had features of TT leprosy in the skin tissue sections while the nerve tissue histopathology showed non-specific changes. Histological features of the skin tissue sections were consistent with the clinical diagnosis in 33 out of 50 cases (66%). When the clinical groups were correlated with the histological features of the nerve tissue sections, concordance was found in 30 of the 50 cases (60%). On comparison of the histological features of skin and nerve tissue sections with the clinical diagnosis, concordance was still lower i.e., 19 out of 50 cases (38%). Thus the histological features of the skin tissue sections correlated more frequently with the clinical diagnosis than did those of the nerve sections. The importance of neural histology lies in the fact that it shows a higher BI and a lower histological grading in some cases and if not performed the lapse can result in inadequate treatment, drug resistance and even relapse.

A patient of pemphigus vulgaris presented with avascular necrosis of the femur after long-term high-dose corticosteroid therapy. Corticosteroids used on a long-term basis can cause avascular necrosis of bone and this has been seen in various diseases. This is attributable to both the disease process itself and the therapy i.e. corticosteroid usage. In dermatological practice avascular necrosis of bone has been seen more commonly with SLE and also with psoriasis using long-term steroids. Avascular necrosis in a case of pemphigus on steroid therapy is a rare finding. We report such a case of pemphigus vulgaris developing avascular necrosis of bone following corticosteroid therapy.

Viral encephalomyelitis is an unusual and the most serious manifestation of infections caused by Flaviviruses, a group of small arboviruses with over 68 species including, West Nile virus, St Louis encephalitis virus, yellow fever virus, dengue virus and zika virus. Case Description: A 77-year-old male with a past history of hypertension and coronary artery disease, presented with high-grade fever, confusion, watery diarrhea and petechial rash on the lower extremities for one week during the month of September. No reported exposure to sick contacts, travel history, known tick or mosquito bites. Hemodynamics were stable but he was febrile (103 F) and lethargic. Neurological examination revealed diminished right corneal reflex, neck stiffness, positive Brudzinski and Kernig signs, quadriparesis (right greater than the left) with increased muscle tone, right leg clonus, bilateral absent lower extremity deep tendon reflexes and positive Babinski sign. Initial labs and imaging studies were unremarkable. Neutrophilic pleocytosis on CSF analysis prompted initiation of antibiotics (vancomycin, ampicillin, cefepime) and acyclovir. His neurological status continued to deteriorate and he developed "locked in syndrome" by the third day of hospitalization. Electromyography and pyridostigmine testing ruled out GBS and myasthenia gravis respectively. Blood and CSF cultures, CSF tick-borne panel, Leptospira, Lymphocytic choriomeningitis virus, Mycoplasma, and HSV were all negative. CSF studies revealed positive West Nile Virus (WNV) IgM and IgG. Later, Arbovirus serology demonstrated high titers of Saint Louis encephalitis (SLE) virus (1:1280). Repeat MRI brain showed abnormal enhancements in the cerebellum and pons. Hence, our patient was diagnosed with neuroinvasive viral encephalomyelitis and treatment with Interferon alpha and IV immunoglobulins was started resulting in substantial improvement within a few weeks. Discussion: Among Flavivirus encephalitids, WNV encephalitis and SLE are the two major public health threats in North America with common mode of transmission through mosquito bites. While encephalitis is not so uncommon, viral encephalomyelitis is an unusual neuroinvasive manifestation of these infections developing in less than 1% of the patients. Asymmetrical flaccid paralysis is the hallmark while other manifestations include meningoencephalitis, ophthalmoplegia, locked in syndrome and diaphragmatic paralysis due to brain stem involvement. Encephalitis is managed conservatively in the majority of the cases with more aggressive treatment in neuroinvasive forms. Treatment modalities for all forms of Flavivirus encephalitis are the same with ongoing research demonstrating some role of ribavirin, interferon alpha and IVIG. Prognosis is usually guarded which emphasizes more on the early recognition and timely initiation of appropriate treatment.