Journal of Clinical Immunology and Allergy

INTRODUCTION

Unilateral laterothoracic exanthemis a self-limited disease that occurs most commonly in children. It is characterized by unilateral exanthem, often in axillary region. The etiology is unknown but a viral agent is suspected.

We report a 9-year-old girl withunilateral laterothoracic exanthem that occur during corona virus pandemic SARS-CoV-2.

The disorder was first described in 1962 and the term “unilateral laterothoracic exanthem” (ULTE) was introduced in 1992. It occurs most commonly in toddlers and preschool aged children with an age range of 6 months to 10 years, male : female ratio is 1 : 2. The etiology of ULTE remains unknown viral etiology have been suggested and screening for multiple viruses (e.g. EBV, CMV, HHV-6, HHV-7) was performed, no etiologic agent has been consistently demonstrated. A relationship to infection with Spiroplasma, parvovirus B19, and EBV has been noted in individual cases. seasonal pattern has been described, occurring more frequently in winter or spring time. Usually preceded by a prodromal upper respiratory or gastrointestinal upset, and is characterized by unilateral and localized exanthem, often in the axillary region, that spreads in a centrifugal pattern, sometimes involving the contralateral side. The mucous membranes, face, palms, and soles are generally spared. The eruption lasts 4 to 6 weeks, exceptionally more than 8 weeks, and transient dryness or minimal post inflammatory hyperpigmentation of the skin subsides. Mild local lymphadenopathy has been found in about 50% of cases. A skin biopsy is usually not helpful, since histopathologic examination discloses only nonspecific superficial dermatitis features, such as perivascular and periappendageal lymphocytic infiltrate, mononuclear cell exocytosis, spongiosis, and lichenoid dermatitis with parakeratosis.

Case report

A 9 years old school girl , medically free was referred to our Dermatology Department during SARS-CoV-2 pandemic for an acute thoracic exanthema over her left axillae evolving for 10 days. The patient was in her usual state of health until she notices rash that started gradually over the left axillae as solitary annular eczematous lesion that started to disseminate to the ipsilateral hemithorax, abdomen and left thigh following dermatome and not crossing the midline associated with itchiness and pain especially after sweating .There were no history of medication exposure such as topical medication, deodorant or any antiperspirant, same lesion before, animal contact ,contact with sick patient , No history of fever, throat pain, cough or runny nose, Other systemic review were unremarkable. ON examination Patient look well, afebrile her vital signs all with in normal. Over the left axillae and ipsilateral hemithorax there is solitary 4x5 cm annular erythematous to brownish eczematous lesion covered with fine scales over the edge, surrounded by smaller coalescing erythematous papules and plaques some with annular configuration. over the left thigh there is solitary annular eczematous plaque 2x3 cm with fine scales over the edge. Wood lamp test have done over the all lesion which came negative. The remaining tegument examination was unremarkable and there was no mucous membrane involvement, the remaining physical examination, including lymph nodes was normal. The patient’s initial laboratory data showed a complete blood count and chemistry within the normal ranges bacterial cultures and titters were negative as were also viral serologies, including those for herpes simplex virus 1 and 2, parvovirus B19, cytomegalovirus (CMV), human herpes virus 6 and 7, andEpstein-Barr virus(EBV). skin biopsy was suggested by the physician but the parents refuse as they know about the disease process. History ,physical examination and laboratory findings were consistent with diagnosis of ULE. we educate the parents about the disease process, skin care routine for such area and to avoid topical irritant if any. Topical corticosteroid with miconazole applied twice a day for two week ,fucidin cream twice a day for 5 days, antihistamine syrup once a day prn if there is itchiness ,patient didn’t come to the follow up due to SARS-CoV-2 pandemic at the time but her mother sent for us the picture of the lesion through teledermatology services patient is improving by our approach and all lesions started to resolve by itself.

Discussion

Unilateral laterothoracic exanthemis a benign self-limited disease that spontaneously resolves in 3 to 6 weeks only requiring parent reassurance. UTLE is typically preceded by nonspecific systemic symptoms, including low-grade fever, diarrhea, or rhinitis. Although most often seen in children, UTLE can affect adults., and is characterized by a unilateral and localized exanthem, often in the axillary region, that spreads in a centrifugal pattern, sometimes reaching the contralateral side.

The etiology is unknown some authors have speculated about a possible relationship with Spiroplasmainfectionbut it has not been confirmed other possible causes is pityriasis rosea, which is often atypical in children.Others believe that viral infection and ULE are coincidental rather than having a causal relationship, since viral infections are common in children. The frequent early age of onset, the seasonal pattern, the associated prodrome, the lack of response to systemic antibiotics, as well as the possibility of familial cases, suggest an infectious cause.

ULE is a cutaneous condition that can be associated with various microorganisms, such as parainfluenza 2 and 3, adenovirus, parvovirus B19,human herpes 6 and 7, and reactivation of EBV or CMV.

In studies in which screening for multiple viruses was performed, no etiologic agent has been consistently demonstrated a relationship to infection with Spiroplasma, parvovirus B19, and EBV has been noted in individual cases.

References

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