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Published on: December 15, 2011
Fas-ligand staining in non-drug- and drug-induced maculopapular rashes
Etienne C E Wang1, Joyce S S Lee, Audrey W H Tan
1National Skin Centre, Singapore, Singapore. etienne@nsc.gov.sg
Background:
Morphologically and histopathologically, drug- and non-drug-induced maculopapular rashes can be almost indistinguishable. It has been postulated that Fas-ligand (Fas-L) is involved in the pathogenesis of drug rashes but not in the genesis of rashes, such as viral exanthems, that are not induced by medications.
Aim:
This study sought to determine if epidermal Fas-L is a distinguishing feature in the pathology of drug and non-drug maculopapular rashes.
Methods:
Archived skin biopsies of patients with a confirmed diagnosis of drug or non-drug maculopapular rashes (n = 10 each) and positive and negative controls were retrieved for immunohistochemical staining for Fas-L. The proportion of Fas-L-positive skin biopsies were compared. The presence of tissue eosinophilia was also evaluated.
Results:
Ten percent of non-drug-induced rashes were Fas-L positive compared to 50% of drug rashes (p = 0.05). Twenty percent of non-drug exanthems had moderate tissue eosinophilia, while 60% from drug rashes had moderate to dense tissue eosinophilia (p = 0.17).
Conclusion:
There is a trend toward Fas-L being more prevalent in the epidermis of drug maculopapular rashes, although this did not reach statistical significance. This is possibly because of the small sample size.
