| Granuloma multiforme | |
|---|---|
| Other names | Mkar disease and Granuloma multiforme (Leiker)[1] |
| Specialty | Dermatology  |
Granuloma multiforme is a cutaneous condition most commonly seen in centralAfrica, and rarely elsewhere, characterized byskin lesions that are on the upper trunk and arms in sun-exposed areas.[2]: 707 It may be confused withtuberculoid leprosy, with which it has clinical similarities. The condition was first noted by Gosset in the 1940s, but it was not until 1964 that Leiker coined the term to describe "a disease resembling leprosy" in his study inNigeria.[3]
The upper trunk and arms are the main areas affected. The clinical picture differs greatly. Typically, the first lesions arepapules, which quickly develop into polycyclic andannular lesions with papular or nodular margins. There might also be plaques that are elevated. Lesions typically leave behind residualhypopigmentedmacules and extend with central healing over months or years. It irritates and is itchy, particularly when new lesions are developing. The lesions differ fromleprosy in that they do not exhibit nerve enlargement, local sensation impairment, or impaired sweating. Also, the lesions never become ulcerated. The illness is a cause of cosmetic disfigurement, but it does not affect the patient's overall health.[4]
Granuloma multiforme is primarily thought to be caused by cumulative photodamage to the dermalcollagen, with the lesions in this condition almost exclusively occurring in sun-exposed areas.[3]
The best way to understand the histologic features is to look at aradial biopsy with a raised border and central zone. The absence ofelastic fibers, the disease's hallmark, is best shown in the central zone using an elastic tissue stain likeVerhoeff-Van Gieson's. A zone of transition with granulomatous infiltration is visible on the elevated border. Both a perivascularlymphocytic infiltrate and elastic tissuephagocytosis are seen within thegiant cells.[5]
Other conditions that should be taken into account in the differential diagnosis of granuloma multiforme includesarcoidosis,necrobiosis lipoidica diabeticorum,granuloma annulare, and the typical mimic oftuberculoid leprosy,[3] which has sensory impairment and thickening of the nerve trunk but no degeneratedcollagen.[6] In younger age groups,granuloma annulare is characterized by asymptomatic lesions that histopathologically show increased mucin deposition encircled by a granulomatous zone with a scarcity ofgiant cells with fewernuclei.[3]Necrobiosis lipoidica is characterized by a yellow-colored appearance of the plaques,telangiectasia, involvement of the lower limbs, as well as the presence offibrosis mixed withnecrosis, vessel wall changes, and fat deposition in the deepreticular dermis.[6]
Althoughtopical steroids have been tried, there is currently no effective treatment for granuloma multiforme.[5]