Erythema Multiforme Associated with Herpetic Pharyngitis

A 22-year-old female presented with severe throat pain of two days duration with fever. Clinical examination revealed multiple small ulcerative lesions in the left side of the oropharynx involving the anterior pillar of the tonsil and the uvula (Figure 1). A clinical diagnosis of herpetic pharyngitis was made, and the patient was started on valacyclovir. The patient developed multiple non-pruritic exanthematous erythematous lesions in the lower limbs on the third day after initial symptoms (Figure 2). A short course of oral prednisolone was started, and the rashes resolved by the 10th day. There was no recurrence of the symptoms at later follow up.

Figure 1.

View of herpetic lesions on the palate and the uvula

Figure 2.

View of erythematous lesions on the lower limbs

Erythema multiforme (EM) is a hypersensitivity reaction of the skin to various agents with typical cutaneous and/or mucosal manifestations (1). The condition is often self-limiting but may be recurrent. The presentation of EM may vary, but most of the lesions are erythematous papular lesions. HSV is the most common microbial agent causing EM and accounts for 50% of the cases (2). HSV associated EM can recur at times and may be precipitated by exposure to sun (3). Various mechanisms have been postulated regarding the pathogenesis of EM. Mostly it is considered to be a Type 4 hypersensitivity reaction mediated by T lymphocytes. This may be triggered by numerous pathogens like HSV I, HSV II, Mycoplasma pneumonia, EBV, HIV, cytomegalovirus, Mycobacterium leprae and Varicella-zoster virus. Various medications and vaccines are also known to precipitate such lesions (4).