Case Report: Pemphigoid Nodularis-Five Patients With Many Years of Follow-Up and Review of the Literature

Hypertrophic Lichen Planus: An Up-to-Date Review and Differential Diagnosis

CONTEXT.—

Hypertrophic lichen planus (HLP) is a variant of lichen planus that can be difficult to diagnose based on histopathologic features alone. Thus, patient clinical history and clinicopathologic correlation are essential considerations to make the correct diagnosis.

OBJECTIVE.—

To discuss the clinical and histologic presentation of HLP and provide a thorough review of commonly encountered mimickers in the differential diagnosis.

DATA SOURCES.—

Data were derived from a literature review, personal clinical and research experiences, and a review of cases in the archives of a tertiary care referral center.

CONCLUSIONS.—

In general, HLP involves the lower extremities and is characterized by thickened, scaly nodules and plaques that are often pruritic and chronic in nature. HLP affects both males and females and is most common in adults 50 to 75 years of age. Unlike conventional lichen planus, HLP tends to have eosinophils and classically displays a lymphocytic infiltrate most concentrated around the tips of rete ridges. The differential diagnosis for HLP is broad and encompasses numerous entities in many different categories, including premalignant and malignant neoplasms, reactive squamoproliferative tumors, benign epidermal neoplasms, connective tissue disease, autoimmune bullous disease, infection, and drug-related reactions. Therefore, a high index of suspicion must be maintained to avoid a misdiagnosis and potential inappropriate treatments.

A case of bullous pemphigoid following administration of anti-IL-31 receptor A antibody

Bullous pemphigoid (BP), an autoimmune bullous dermatosis, occurs predominantly in older individuals. Nemolizumab, a humanized monoclonal antibody against the interleukin (IL)-31 receptor A, is used to treat severe atopic dermatitis (AD) in Japan. However, it can cause several adverse events, such as exacerbation of AD, erythema, and eosinophilia. Herein, we describe a case of prurigo-type AD developing BP after nemolizumab administration. A 62-year-old man with prurigo-type AD and asthma presented with serious, refractory itching. After nemolizumab injection, his pruritus was relieved for 2 days. However, on day 3, erythema with blisters and erosions suddenly appeared throughout his body. Pathological examination showed typical BP and the patient's serum anti-BP180-NC16a antibody level was 882.5 U/mL. Oral prednisolone (PSL) was initiated and nemolizumab was never used again. Despite high-dose PSL, new blisters continued to develop, with a rapid elevation of anti-BP180-NC16a antibodies to 6930 U/mL. Adding high-dose cyclosporine and intravenous gamma globulin reduced new blister formation after 9 weeks, and PSL and cyclosporine were gradually tapered. Dupilumab, an anti-IL-4 receptor antibody, was initiated after 16 weeks, resulting in continued remission without PSL and cyclosporine. The sudden occurrence of BP in this case suggested that the patient had occult BP before the nemolizumab initiation and that nemolizumab exacerbated BP and made it overt. Blocking the IL-31 pathway may exacerbate inflammation in AD or BP, resulting in the acceleration of blister formation. This may be countered by blocking the IL-4/13 pathway with dupilumab. To our knowledge, this is the first case of nemolizumab-exacerbated BP.

Generalized Nodules in an Older Adult Man

A man in his 60s presented with an 8-month history of pruritic papulonodular lesions on his extremities and trunk, with no significant improvement with steroids and antihistamines. What is your diagnosis?