Under-reported Finding in Acral Erythema Multiforme.

Erythema multiforme is an acute muco-cutaneous hypersensitivity reaction with a variety of etiologies. It is characterized by a skin eruption, with or without oral or other mucous membrane lesions. General characteristics and treatmet have been described, but nail findings are rarely reported Here we present a 26-year-old patient with acral erythema multiforme and erythronychia adjacent to skin lesions on the back of the hands. To our knowledge this association had not been reported before.

What was known?

Erythema multiforme is a self-limited, mucocutaneous disorder

It can affect the nail bed causing edema of the nail folds and nail plate detachment.

Introduction

Erythema multiforme (EM) is a common self-limited mucocutaneous disorder. It predominantly affects younger individuals showing a slight male predilection. Certain virus or drugs can trigger an immune response against the keratinocyte; causing epidermal necrosis and the appearance of the classic targetoid skin lesions.[12]

There are few reports of nail changes in this entity. Previously reported nail changes are edema of the nail folds and nail plate detachment. In some cases of EM, these changes can cause permanent nail deformity, therefore early diagnosis is crucial in order to prevent permanent sequelae.

Case Report

A 26-year-old man visited the dermatology clinic at the National Institute of Medical Sciences “Salvador Zubirán” with several skin lesions in upper extremities, palms and soles. Physical examination revealed widespread red and targetoid macules with dusky centers, with adjacent irregular erithematous areas in the nail bed. [Figures 1 and 2]. He referred oral ulcers, fever, chills and the use of a nonsteroidal anti-inflammatory drug (NSAID) 3 days before the onset of the lesions. Based on the clinical findings and the presence of oral ulcers before the onset of the skin lesions, the diagnosis of EM secondary to herpes simplex virus infection was made.

Figure 1

Erythematous papules and targetoid lesions. (a) Back of the hands. (b) Palms. (c) Nails

Figure 2

Dermoscopic findings in nails (DermLite DL1)

Discussion

EM is an acute, immune-mediated, mucocutaneous condition. Several factors have been linked to the development of EM. In fections represents up to 90% of cases, and the most common agent is herpes simplex virus (HSV). Drugs like NSAIDs, sulfonamides, antiepileptics and antibiotics have also been implicated in the development of this disease. Less frequently it is associated to autoimmune disorders, malignancy, immunizations, radiation, and menstruation. The clinical findings are characterized by acrally distributed, targetoid lesions with concentric color variation that sometimes can be accompanied by mucosal erosions. The diagnosis is based on clinical findings.[13]

The pathogenesis is not well known. HLA DQB1*0301, A33, B35, B62, DQ3 and DR53 have been related to this disease, therefore genetic susceptibility can be a predisposing factor.[6] Cell-mediated immune reaction against viral antigen-positive cells and several inflammatory mediators have been implicated in the pathogenesis of his disease.[145]

Frequently is accompanied by prodromal symptoms such as malaise, fever, and mialgias. The earliest lesions of EM are round, erythematous, edematous papules. After several days these lesions develop concentric alterations in color resulting in targetoid lesions. Appearing in the distal parts of the extremities and spread in a centripetal manner. Generally it is a self-limiting disease.[1] The most important differential diagnosis are reaction to arthropod bites, Behçet disease, fixed drug eruption and acute febrile neutrophilic dermatosis.[3]

There are few reports that describe the nail changes in this entity. Edema of the nail folds and nail plate detachment with subsequent nail deformity are some of the nail findings that have been reported.[16] In our case, several localized areas of erythema in the nail bed were documented by first time. These erythematous areas are adjacent to the skin lesions of EM, so this nail change may be explained by the inflammatory process that cause vessel dilatation with an alteration of the blood supply in the nail bed.[7]

The patient was treated with topical corticosteroids twice at day with resolution of his lesions in 10 days without sequelae.

In conclusion, nail findings in inflammatory conditions are underestimated. It is important to report the variability of the nail changes in these conditions with the aim of early diagnosis, treatment and sequelae prevention.

What is new?

The nail changes en erythema multiforme are underestimated

Erythronychia is a new nail finding in this disease that had been not previously reported.