Erythema nodosum is the most common type of panniculitis; it may be due to a variety of underlying infectious or otherwise antigenic stimuli. The pathogenesis remains to be elucidated, but both neutrophilic inflammation and granulomatous inflammation are implicated. Beyond treating underlying triggers, therapeutic options consist mainly of nonsteroidal anti-inflammatory drugs, symptomatic care, potassium iodide, and colchicine. Erythema induratum (nodular vasculitis) is a related but distinctly different clinicopathologic reaction pattern of the subcutaneous fat. It is classically caused by an antigenic stimulus from Mycobacterium tuberculosis but may be associated with several other underlying disorders. After appropriate antimicrobial treatment in tuberculous cases, therapy for erythema induratum is similar to options for erythema nodosum.

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Systemic glucocorticosteroids (GCS) remain a first-line therapy for a variety of dermatologic diseases. The purpose of this article is to review the major pharmacologic properties and drug interactions of GCS, as well as the mechanisms of action, dosing and delivery options, and major adverse effects. In addition, the present authors will discuss the major indications and practical suggestions for the use of systemic GCS in dermatology.

Liesegang rings represent an in vivo chemical precipitation phenomenon representing a potential diagnostic pitfall for misdiagnosis as parasitic infections. These acellular patterns of lamellar concretions are rare in human tissue. The authors report a case of Liesegang rings observed within an intradermal apocrine hidrocystoma and review the literature for reports of these structures, with particular emphasis on mucocutaneous lesions.