Pemphigus‐like eruption as a complication of molluscum contagiosum treatment with imiquimod in a 5‐year‐old girl

Abstract

Pemphigus and pemphigus‐like reactions can be triggered by a variety of medications including topical therapies, such as imiquimod. While the association between imiquimod and pemphigus‐like reactions has been reported in adults, this is the first report of a generalized reaction beyond the site of imiquimod application in a child. The mechanism by which this occurs may be through a unique pathway, separate from the classic antibody‐mediated pathway. Our patient had a full recovery without recurrence after cessation of the inciting drug.

Imiquimod-Associated Pemphigus Foliaceus

“…Table 1 summarizes the clinical and laboratorial data of the previous 7 cases (4 PF and 3 PV). [9][10][11][12][13][14][15] Although the histopathological examination was not the characteristic of PF, the typical clinical presentation, the DIF and IIF data, and the anti-Dsg-1 positivity results supported the PF diagnosis. Despite not being commonly described in pemphigus, the presence of eosinophils in the skin biopsies of the compiled cases (Table 1) deserves attention.…”

“…Despite not being commonly described in pemphigus, the presence of eosinophils in the skin biopsies of the compiled cases (Table 1) deserves attention. 11,12,15 Furthermore, the only description of IgA on DIF referred to our case.…”

Rare Cutaneous Side Effects of Imiquimod: A Review on Its Mechanisms, Diagnosis, and Management

“…Among the recognized exogenous predisposing factors, drugs are the most common trigger [ 84 , 85 ]. Long-term systemic IFN-α treatment could induce pemphigus by stimulating the production of antiepidermis antibodies, most commonly the pemphigus type, by autoreactive B cells [ 86 – 88 ]. Thus, as an inducer of IFN-α production, imiquimod may indirectly induce the upregulation of pemphigus autoantibodies and subsequent development of pemphigus [ 22 ].…”

“…To date, only eight cases have been reported, including one that involved a 5-year-old child (summarized in Table 3 ). The clinical variants included pemphigus foliaceus [ 89 , 90 ], pemphigus vulgaris, pemphigus vegetans [ 91 ], and a pemphigus-like reaction [ 88 ].…”

Soluble Factors and Receptors Involved in Skin Innate Immunity—What Do We Know So Far?

“…On the one hand, a recent case-control study on 48 pediatric patients recommended topical imiquimod as a first-line treatment in children with disseminated lesions [ 71 ]. On the other hand, some scientists found the use of imiquimod in children with molluscum contagiosum not only inefficient but also hazardous, considering high systemic absorption, hematological abnormalities [ 72 ], and even pemphigus-like eruption as side-effects [ 73 ].…”