https://orcid.org/0000-0002-5920-7095
ABSTRACT
The diagnosis of cutaneous lupus erythematosus (CLE) presents a challenge due to its heterogeneous nature. This is especially true in cases of discoid lupus erythematosus (DLE), which in the past has not had clearly defined diagnostic criteria. The recent development of classification criteria for DLE has made its diagnosis more straightforward; however, some cases previously called DLE must now be reclassified.
In Reply: We would like to thank Dr Cohen for his thoughtful letter in response to our review article titled ‘Cutaneous lupus erythematosus induced by drugs – novel insights’. The list of drugs implicated in cutaneous lupus erythematosus (CLE) is expansive and continues to grow. These cases are primarily drug-induced subacute CLE (SCLE), though rarely drug-induced chronic CLE has been described. Chronic CLE manifests most commonly as discoid LE (DLE), which historically has been a diagnostic challenge due to poorly defined diagnostic criteria. Thanks to formal classification criteria recently described for DLE this diagnosis is more straightforward; however, many cases previously thought to represent DLE must now be reclassified [Citation1].
Using the Delphi method, Elman et al. agreed upon a set of 12 classification criteria for DLE based on the morphology, histopathology, and location of lesions. Morphology consists of five criteria: erythematous – violaceous in color, atrophic scarring, dyspigmentation, follicular hyperkeratosis/plugging, and scarring alopecia. Histopathology includes interface/vacuolar dermatitis, peri-vascular and/or peri-appendageal lymphohistiocytic infiltrate, follicular keratin plugs, mucin deposition, and basement membrane thickening. Finally, location of lesions includes location in the conchal bowl and preference for the head and neck [Citation1].
Based on these classification criteria we are hesitant to agree that the reported cases of fluorouracil induced DLE described in Dr Cohen’s letter are truly DLE. While the biopsy in the case from Yoshimasu et al. supports the diagnosis of CLE, we believe there is not enough information to assert that this is DLE specifically [Citation2]. In Dr Cohen’s case, a biopsy may help support that this is CLE, though without this information we would include other drug-induced cutaneous diseases in the differential diagnosis such as seborrheic dermatitis or erythematotelangiectatic rosacea [Citation3]. Particularly, the absence of scarring, a hallmark of DLE, leads us to this conclusion. In addition, we do not suggest the use of antibodies, specifically anti-SSA/Ro to help differentiate the subtypes of CLE. There are numerous reports of anti-SSA/Ro present in CCLE, though often at lower titers than SCLE [Citation4–6]. The absence of anti-SSA/Ro antibodies also does not exclude the diagnosis of SCLE as 20–60% of the SCLE patients can be negative depending on the laboratory testing method used [Citation7,Citation8].
The diagnosis of CLE is a challenge due to its heterogeneous nature. Recent classification criteria developed for DLE have helped to differentiate CLE subtypes in cases that have overlapping features. In the absence of features such as scarring or alopecia, it is difficult to confidently diagnose DLE. In addition, a biopsy may support the diagnosis of CLE but there are no specific features that can reliably differentiate the subtype of CLE [Citation9]. Based on this information, we believe it prudent to categorize these cases of fluorouracil induced CLE as SCLE rather than DLE.
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
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References
- Elman SA, Joyce C, Nyberg F, et al. Development of classification criteria for discoid lupus erythematosus: results of a Delphi exercise. J Am Acad Dermatol. 2017;77:261–267.
- Yoshimasu T, Hiroi A, Uede K, et al. Discoid lupus erythematosus (DLE)-like lesion induced by uracil-tegafur (UFT). Eur J Dermatol. 2001;11:54–57.
- Cohen PR. Discoid lupus erythematosus lesions associated with systemic fluorouracil agents: a case report and review. Cureus. 2020;12:e7828.
- Lee LA, Roberts CM, Frank MB, et al. The autoantibody response to Ro/SSA in cutaneous lupus erythematosus. Arch Dermatol. 1994;130:1262–1268.
- Vera-Recabarren MA, García-Carrasco M, Ramos-Casals M, et al. Comparative analysis of subacute cutaneous lupus erythematosus and chronic cutaneous lupus erythematosus: clinical and immunological study of 270 patients. Br J Dermatol. 2010;162:91–101.
- Biazar C, Sigges J, Patsinakidis N, et al. Cutaneous lupus erythematosus: first multicenter database analysis of 1002 patients from the European Society of Cutaneous Lupus Erythematosus (EUSCLE). Autoimmun Rev. 2013;12:444–454.
- Sontheimer RD. Subacute cutaneous lupus erythematosus: 25-year evolution of a prototypic subset (subphenotype) of lupus erythematosus defined by characteristic cutaneous, pathological, immunological, and genetic findings. Autoimmun Rev. 2005;4:253–263.
- Zappi E, Sontheimer R. Clinical relevance of antibodies to Ro/SS-A and La/SS-B in subacute cutaneous lupus erythematosus and related conditions. Clin Dermatol. 1992;10:431–441.
- Rothfield N, Sontheimer RD, Bernstein M. Lupus erythematosus: systemic and cutaneous manifestations. Clin Dermatol. 2006;24:348–362.