fixed drug eruption ( fde ) is a distinctive variant of drug induced dermatoses characterized by sharply demarcated , erythematous patches with / without blistering that develop within hours of administration of the causative drug and heals with postinflammatory residual hyperpigmentation . it usually recurs at the same site of the skin or mucous membrane upon subsequent exposure to the same / similar group of drugs . fluoroquinolones are widely used antimicrobials , which cause cutaneous adverse drug reactions in about 1 - 2% of patients . however , bullous fde is rarely reported . herein we report a rare case of fde induced by ciprofloxacin followed by ofloxacin administration . a 37-year - old male presented to the outpatient dermatology department of our hospital , puducherry with a history of multiple fluid filled blisters over both hands and feet [ figures 1 and 2 ] . he stated that the lesions appeared within 5 h of taking a single dose of oral ofloxacin , which was obtained as over the counter drug for fever from a local private medical shop . history of itching over both hands and feet followed by a burning sensation and the subsequent development of multiple fluid filled lesions were present . there was no previous history of any medical conditions such as allergy or atopic dermatitis . on further inquiry , he recalled a history of a similar episode about 1 year back for ciprofloxacin , which has been prescribed for fever . at that time physical examination revealed multiple flaccid bullous lesions with intact roof of the blister in an erythematous base were seen over proximal metacarpophalangeal joint of left thumb , left instep of sole , right dorsal big toe and little toe of left foot . diagnosis of fde caused by ofloxacin was made taking into account of previous history of fde induced by ciprofloxacin and clinical signs . patch test was not done as the patient did not give consent for the same . the causative drug ofloxacin was discontinued and the patient was treated with antihistaminics and topical emollients . the lesions and symptoms improved gradually within a week leaving behind residual hyperpigmentation and the patient was advised not to take fluoroquinolones in future . well - defined bullous lesion in the instep of left foot bullous lesions in the right dorsal toe fluoroquinolones are commonly used antimicrobials ( effective for both gram negative and gram positive bacteria ) in the treatment of various bacterial infections and are generally well tolerated . common side - effects include gastrointestinal effects ( nausea , vomiting and diarrhea ) and neuropsychiatric symptoms ( headache and insomnia ) . photosensitivity and morbilliform rash have been reported with fluoroquinolones , but fde is quite uncommon . a large number of drugs have been reported to elicit fdes such as trimethoprim - sulfamethoxazole , tetracyclines , penicillin , erythromycin , nonsteroidal antiinflammatory drugs , barbiturates , valproate , phenytoin , phenolphthalein , and nitroimidazoles . even though , the pathogenesis of fde is not known , certain serum factors , antibodies , and cell mediated immunity have been attributed as causative factors . localized tissue damage results when intra - epidermal cd t - cells are activated to kill surrounding keratinocytes and release cytokines such as interferon - gamma into the microenvironment . quinolones can cause both delayed type and ige - mediated hypersensitivity reactions . in this case , the following criteria were considered : there were previous conclusion reports on this reaction ( + 1 ) ; the adverse event appeared after ofloxacin was administered ( + 2 ) ; adverse event improved when ofloxacin was discontinued ( + 1 ) ; adverse event reappeared when ofloxacin was re - administered ( 0 ) ; alternate causes that could solely have caused the reaction ( + 2 ) ; the reaction reappeared when a placebo was given ( 0 ) ; drug detected in the blood ( or other fluids ) in a concentration known to be toxic ( 0 ) ; the reaction was more severe when the dose was increased or less severe when the dose was decreased ( 0 ) ; the patient had a similar reaction to ciprofloxacin in the previous exposure ( + 1 ) ; the adverse event confirmed by objective evidence ( + 1 ) . probable  reaction to ofloxacin administration . according to who - uppsala monitoring centre causality assessment system patient had fde to ciprofloxacin 1 year back followed by similar reaction to ofloxacin in the current admission . cross - reaction between quinolone families , clinically manifested as fde , has been rarely reported in the literature . to the best of our knowledge , only one case of cross reactivity between ciprofloxacin and ofloxacin has been reported so far which proposed the probable mechanism would be a complex of quinolone and piperazine residue as the antigenic determinant for both ciprofloxacin and ofloxacin . bullous fde due to fluoroquinolones should be included in the differential diagnosis when fde is suspected . our case described the cross sensitivity between two fluoroquinolones ciprofloxacin and ofloxacin used within 1 year interval time . hence , health care providers should be aware of the diagnosis and proper management of fde . patients should be warned against the use of anti - microbials without the physician 's advice .