Unilateral Laterothoracic Exanthem


What is Unilateral laterothoracic exanthem?

It is an uncommon condition characterized by a unilateral, periflexural rash that starts from the axilla or groin and can spread to the face, genitalia or hands. The lesions are red, raised and surrounded by white halos. 

Who is affected by it?

The condition affects mostly children of the age of 2-5 years, but there has been an increase in the number of cases among adults. 

What is the cause?

The cause of unilateral laterothoracic exanthem (ULE) is unknown but exposure to certain viruses are implicated in (UTLE). Epstein Barr virus and parvovirus B19 are commonly associated with UTLE, and most recently with COVID-19. 

How is ULE diagnosed?

Diagnosis is based on clinical presentation and skin biopsy in some cases. If the patient is asymptomatic, no treatment is needed. Emollients and topical steroids are used to relieve the itching. 


ULE resolves without treatment. It can be mistaken for other cutaneous conditions such as contact dermatitis, scabies and a slew of other conditions


Written by: Naif Alalshaikh, medical student.


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Adams SP. Dermacase. Unilateral laterothoracic exanthem. Canadian Family Physician. 1997 Aug;43:1355.