Idiopathic Cutaneous Pseudolymphoma Treated Successfully with Hydroxychloroquine: A Case Report and Literature Review

Hydroxychloroquine (HCQ) has been used for decades to treat patients with rheumatic diseases, for example, systemic lupus erythematosus (SLE), rheumatoid arthritis or the antiphospholipid syndrome (APS). We hypothesise that HCQ might target endosomal NADPH oxidase (NOX), which is involved in the signal transduction of cytokines as well as antiphospholipid antibodies (aPL). Show more

Cutaneous pseudolymphoma (CPL) is a reactive polyclonal T- or B-cell lymphoproliferative process. CPL may appear as localized or disseminated skin lesions. While most cases of CPL are idiopathic, they may also occur as a response to, for example, contact dermatitis, arthropod reactions, and bacterial infections. CPL can be classified based on its clinical features, but all variants have similar histopathological patterns of either predominantly B-cell infiltrates, T-cell infiltrates, or mixed T/B-cell infiltrates. The prognosis of CPL is good, but the underlying disease process should be taken into account. If an antigenic stimulus is identified, it should be removed. In patients with idiopathic CPL, a close follow-up control strategy should be adopted. The aim of this systematic review is to summarize all reported treatments for CPL. The review was based on articles from the PubMed database, using the query "skin pseudolymphoma treatment", English and German, about "human" subjects, and published between 1990 and 2015 documenting adequate treatment and/or aetiology. Mainly individual case reports and small case series were found. Treatment options include topical and intralesional agents, systemic agents, and physical modalities. The final part of the review proposes a treatment algorithm for CPL according to each aetiology, based on the literature of the last 25 years. Future research should focus on randomized controlled trials and studies on long-term outcomes, which were not identified in the current review. Show more

Hydroxychloroquine is one of the most frequently used drugs in dermatology with a wide variety of uses due to its immunomodulatory, anti-inflammatory, photoprotective, and metabolic actions and low side effect profile. Demonstration of its antiviral action in vitro has led to renewed interest by physicians worldwide during the ongoing coronavirus disease of 2019 (COVID-19) pandemic. Like its immunomodulatory action, its antiviral activity is also due to its ability to alkalinize the intracytoplasmic milieu, leading to disordered viral entry/fusion and deranged viral protein synthesis. However, randomized controlled trials are the need of the hour to conclusively determine its clinical efficacy in such infections. A review of the multitude of mechanisms of action, updated screening and monitoring guidelines, drug interactions, side effects, and its use in special populations is described. Show more