DP08: Leprosy unmasked by COVID‐19 infection: a new diagnosis of leprosy with development of type 1 reversal reaction

Abstract

The plaguing plaques of progressive nodular nonLangerhans histiocytosis M. Hunjan, P. Boesch and A. Mehta Solihull Hospital, University Hospitals Birmingham NHS Trust; College of Medicine and Dentistry, University of Birmingham; and Corbett Hospital, Dudley Group of Hospitals NHS Trust, Birmingham, UK A 92-year-old woman was referred by her general practitioner to a rapid-access plastic surgery skin cancer clinic with a lesion on the right side of her neck suspicious for cutaneous malignancy. She gave a few-years’ history of an increasing number of multiple, annular, indurated lesions on her scalp and neck that were increasing in size. The lesions were completely asymptomatic. Her past medical history included hypertension, atrial fibrillation, chronic obstructive pulmonary disease, chronic kidney disease and IgG lambda paraproteinaemia. Clinically, there were foul-smelling yellow, waxy plaques over her left occiput and the right side of her neck. The initial impression was that these were ulcerated basal cell carcinomas. She had no palpable lymphadenopathy. She was booked in to have incisional biopsies from each of the lesions. The biopsy showed a spindle-cell proliferation through the full thickness of the dermis. These cells had eosinophilic cytoplasm, vesicular nuclei, thin nuclear membrane and nuclear folds. There were also multinucleated giant cells, some of Touton type. There were scattered small lymphocytes. Foci of necrobiosis were noted. There were scattered mitoses and apoptosis. Ziehl–Neelsen and periodic acid–Schiff stains were negative. Lesional cells were positive for CD4 and CD68. Langerhans cell immunochemistry was negative. Features were consistent with non-Langerhans cell histiocytosis-progressive nodular type. Non-Langerhans histiocytosis compromises a spectrum of diseases, of which progressive nodular histiocytosis (PNH) is one. It predominately affects those in their twenties and thirties. Patients usually present with multiple yellowish–brown papulonodules, which vary in size, affecting the head, neck, limbs and trunk, and can be cosmetically disfiguring. The lesions tend to be asymptomatic; however, there has been an isolated report of fatal laryngeal involvement. Although not typically associated with underlying conditions, there have been reports of PNH associated with Earle disease and autoimmune diseases such as rheumatoid arthritis. It is characterized histologically by a diffuse infiltrate of spindleshaped histiocytes, admixed with xanthomatized histiocytes and Touton giant cells, in the dermis. In addition, lesional cells stain positively for CD4 and CD68, and Langerhans immunochemistry is negative. PNH is a very rare entity with a progressive, although largely benign, course. Spontaneous resolution has yet to be reported. Treatment should be guided by the extent of disease and patient preference. Therapeutic options include surgical excision and methotrexate, to help slow down progression of disease. DP08 Leprosy unmasked by COVID-19 infection: a new diagnosis of leprosy with development of type 1 reversal reaction E. Keeling, S. Nestor, T. Fitzgerald, A. Alani and A. Murphy Galway University Hospital, Galway, Ireland The global incidence of leprosy (or Hansen disease) is falling, but the disease can still present in the most unexpected places. Leprosy can be difficult to diagnose outside endemic areas, leading to serious consequences. In the UK, a delay in diagnosis occurs in 82% of cases. We present a challenging case of leprosy in Ireland, unmasked by COVID-19 infection. A 30year-old Brazilian man living in Ireland was admitted to hospital with confirmed COVID-19 infection. He gave an incidental 2-year history of tingling and numbness of the digits, accompanied by a nonspecific rash on the hands and face. Dermatological examination revealed numerous raised erythematous plaques on his face and hands with tense bullae accompanied by superficial erosions along the metacarpophalangeal and proximal interphalangeal joints. Reduced sensation to light tough was identified in both hands and feet. Biopsy of the plaques revealed non-necrotizing epithelioid granulomas within the dermis, involving cutaneous nerves. Ziehl– Neelsen (ZN) stain highlighted numerous organisms within the granulomas. Alcian blue/periodic acid–Schiff (PAS) stain and direct immunofluorescence were negative. Based on these findings a diagnosis of lepromatous/borderline lepromatous leprosy was made. The infectious disease team was consulted and triple therapy of dapsone (100 mg), rifampicin (600 mg) and clofazimine (50 mg) was commenced, resulting in some improvement of cutaneous manifestations. However, 7 months later, progressive symptoms resulted in the clawing of both hands, symmetrical hyperpigmented linear plaques on the cheeks and ichthyosis of the lower limbs. Sensory deficit to light touch extended from fingers to wrists. Further skin biopsies of the facial plaques revealed neurotropic dermal granulomatous inflammation composed of small collections of histiocytes in the dermis associated with a mild lymphocytic periadnexal infiltrate. ZN and PAS stains were negative, with no organisms identified. Oral steroids (prednisolone 40 mg once daily) were added to his therapeutic regime for what was thought to be a type 1 reversal reaction with subsequent improvement in cutaneous plaques. At the time of writing, he continues on oral steroids and the cutaneous features have remained stable. The dysregulated immune response in severe COVID-19 infection is associated with a cytokine storm. This may act as a stimulus in triggering leprosy reactions leading to significant complications. With the increasing numbers of COVID-19 cases globally, the number of leprosy cases with COVID-19 is likely to increase, especially in endemic areas. Although rare in developed countries, as clinicians it is important to have a high index of suspicion of leprosy in patients with chronic skin conditions who have travelled to or emigrated from endemic areas.