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An 11-year-old girl developed an asymptomatic rash on her face, arms, and legs that persisted for 3 weeks over the autumn, reported Samar Sheriff, MD, MBA, of the University of Louisville in Kentucky, and colleagues.

Aside from a history of seasonal allergies being managed with cetirizine, she had no other health problems. She had not been ill recently, nor had she received any vaccinations or new medications, the group noted in .

Clinicians performed a review of systems with unremarkable findings. "Physical examination was notable for erythematous annular thin plaques without surface change on her right cheek, an erythematous, edematous plaque on her nose, and erythematous, edematous, annular papules and plaques on her arms, hands, and thighs," Sheriff and team wrote.

They obtained a specimen from the patient's right arm, which was sent to the lab for histopathologic analysis. The team considered several differential diagnoses, including urticaria, cutaneous lupus erythematosus, polymorphous light eruption (PMLE), and an interstitial granulomatous drug reaction (IGD).

Histopathology findings included "a subtle thickened basement membrane zone and lymphocytic perivascular infiltrate," for which topical corticosteroids were prescribed, the authors noted.

Two months later, the patient returned when her rash became worse and she developed new sensitivity to sun.

Laboratory results were positive for the following:

• Speckled antinuclear antibodies (titers ≥1:160)
• Anti-double-stranded DNA antibodies
• Anti-Smith antibodies
• Anti-ribonucleoprotein antibodies
• Anti-Ro/Sjögren syndrome A antibodies

Complete blood count test results included:

• White blood cell (WBC) count: 0.003/μL
• Aspartate aminotransferase: 59 U/L
• Alanine aminotransferase: 69 U/L

The clinicians noted that the patient's WBC count indicated leukopenia. The girl's mother said that the patient had been unusually tired lately, and had complained of a sore stomach and painful shoulder.

"The patient demonstrated overlapping features of acute cutaneous lupus erythematosus (ACLE) and subacute cutaneous lupus erythematosus (SCLE), pointing to systemic lupus erythematosus (SLE)," Sheriff and colleagues wrote.

They classified her disease as SLE, based on her elevated levels of antinuclear antibodies >1:80 -- the entry-level diagnostic criterion for SLE -- and her score of 21 weighted points across four different domains according to the American College of Rheumatology/European Alliance of Associations for Rheumatology for the diagnosis of SLE (the minimum requirement is 10 points).

The clinicians recommended use of sun protection, which they reported improved the patient's rash dramatically. She was referred to rheumatology, and started treatment with 200-mg hydroxychloroquine 5 days per week.

Assessment of her liver raised concerns that she had lupus hepatitis, the authors noted, but "test results for viral hepatitis, autoimmune hepatitis, celiac disease, α1-antitrypsin deficiency, and elevated α1-fetoprotein were negative."

Discussion

"This case report details a unique presentation of ACLE and SCLE overlapping as initial signs of SLE in a pediatric patient," Sheriff and co-authors wrote.

Younger patients are more likely to present with the chronic form of cutaneous lupus erythematosus, as opposed to acute and subacute disease types. "Because the subacute form (SCLE) is exceedingly rare in the pediatric population, this presentation is even more distinctive," they added.

Localized ACLE is associated with photosensitivity and the typical butterfly malar rash, which leaves the nasolabial folds unaffected. In generalized ACLE, a morbilliform rash develops on sun-exposed skin. The subacute form of cutaneous lupus erythematosus tends to present as annular psoriasiform erythematous plaques, with no scarring.

In this patient's case, her photosensitivity fit the presentation of ACLE, while the annular plaques on her arms reflected SCLE. While scales are generally observed in SCLE, they are not required for diagnosis. The authors suggested that this may be the first reported pediatric case of overlapping ACLE and SCLE symptoms, and thus this condition may be underrecognized.

Of the three differential diagnoses considered by Sheriff and colleagues, they noted that is defined by acute development of transient itchy wheals and angioedema, or both. "The histopathologic characteristics include upper dermal edema with a mild mixed perivascular infiltrate of lymphocytes, eosinophils, basophils, and neutrophils," they wrote.

This patient had atypical features including interface dermatitis and the completely asymptomatic, permanent nature of the rash.

PMLE is another common form of photodermatosis in which sun exposure causes itchy lesions to occur on exposed skin, with the exception of the face. A dermatologic manifestation of lupus erythematosus can be difficult to distinguish from PMLE, Sheriff and co-authors noted. Evidence of antinuclear antibodies has been proposed as a means of differentiating lupus erythematosus from PMLE, but recent research suggests that elevated antinuclear antibody titers can also occur in the setting of PMLE.

Histology findings are not helpful in distinguishing PMLE from lupus erythematosus, due to the nonspecific histologic characteristics of PMLE. In this patient's case, PMLE was unlikely given that the symptoms developed in autumn, and included joint pain, leukopenia, and facial rash.

Clinical symptoms of IGD may vary considerably, Sheriff and team said. Skin symptoms are usually asymptomatic and tend to affect the trunk, arms, and legs. Furthermore, they explained, "the histologic characteristics of IGD are characterized by histiocytes scattered throughout the dermis typically arranged around foci of degenerated collagen and may form small granulomas."

Thus, potential IGD can be discounted given the absence of histiocytes and presence of an interface dermatitis that would not occur in IGD.

"This case report highlights diverse lupus erythematosus presentations, emphasizing the need for a thorough workup for prompt diagnosis and treatment," Sheriff and co-authors concluded.

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