C ie Fixed drug eruption Fixed Drug Eruption - Adverse cutaneous drug reaction appearing soon after ingestions (from 30 min to 8-16 hours) of offending agent in previously sensitized individuals - Numerous drugs, including anti-inflammatory agents (eg salicylates, NSAID's including paracetamol), phenylhutazone, phenacetin and dapsone, sulfonamides, tetracycline & mefenamic acid may be responsible - Genital & perianal skin is the most commonly involved siteQ. Neveheless any site may be involved. - Most commonly lesions are solitaryQ but they may be multiple - Lesions evolve from macules to papules to vesicles & bullae and then erode. - Lesions heal by residual hyper-pigmentation Q - Usually asymptomaticQ but may be pruritic, painful, or burning (when eroded) - Lesions persist if drug is continued and resolve days to weeks after drug is discontinued - FDE occurs repeatedly at the same (ie fixed) site within hours, every time drug is taken and heal by residual grayish or slate colored hyperpigmentationQ. On rechallange, not only do the lesions recur in the same location, but also new lesions often reappears Challenge or provocation/Patch test can asceain etiology Herpes genitalis - Multiple, painful, bleeding non-indurated vesicles or ulcer with painful lymphadenopathyQ Pemphigus vulgaris Flaccid intraepidermal bullaeQ on upper pa of body in 40 - 60 years adult with mucosal involvement. Nikolsky sign positive, row of tomb stone & accantholysis presentQ Bechet's syndrome Multisystemic disorder with recurrent oral & genital ulcerations with ocular involvement - Recurrent apthous ulcerations are sine qua non for diagnosis Ulcers heal without leaving scars - Genital ulcers are less common and do not involve glans and urethra