title: Cutaneous reactions due to diltiazem and cross reactivity with other calcium channel blockers.
abstract: BACKGROUND
  The spectrum of cutaneous eruptions in association with calcium channel blockers is extensive, varying from exanthemas to severe adverse events. Reactions due to diltiazem occur more frequently than with other calcium channel blockers. Patch testing has been used as confirmatory testing in patients with extensive cutaneous reactions. Cross-reactivity among these drugs have not been established.
  
  
  METHODS
  We present 3 patients: 1) A 54-year-old man developed a generalized erythema-multiforme-like reaction followed by erythrodermia and exfoliative dermatitis 6-7 days after starting on diltiazem. The drug was stopped and remission was obtained with emollients and systemic corticosteroids and antihistamines within 12 days. 2) A 80-year-old woman experienced a pruritic exanthematous eruption on her trunk which evolved to generalized erythrodermia and superficial desquamation. This reaction appeared 10 days after taking diltiazem, and gradually improved in 10-12 days after discontinuation of this drug. 3) A 79-year-old man presented with erythema and pruritus initially on the back, and then affecting thorax, extremities and face. He had started treatment with diltiazem three days before. Diltiazem was stopped and steroid and antihistamine therapy was given. His skin condition improved, but 3 days later the patient received verapamil with worsening of previous situation. He recovered within 7 days.
  
  
  RESULTS
  Two to six months after the reaction, we carried out epicutaneous tests with calcium channel blockers from different groups. Diltiazem proved positive (at 48 and 96 hours) in the three patients; nifedipine was also positive in patient 2, and verapamil in patient 3. Controlled administration of verapamil was well tolerated in patient 2 after the reaction, and the patient 1 has taken nifedipine without problems.
  
  
  CONCLUSIONS
  1) We report 3 cases of cutaneous reactions due to diltiazem. 2) Epicutaneous tests have been useful for diagnosis. 3) As one of patients had positive patch tests to diltiazem and nifedipine, and other one with diltiazem and verapamil, more studies are needed to demonstrate cross reactions among calcium channel blockers.
authors.affiliation: Servico de Alergología, Hospital Universitario Infanta Cristina, Badajoz, Spain. mgg01ba@saludalia.com
authors.forename: M A
authors.initials: MA
authors.lastname: Gonzalo Garijo
authors.forename: R
authors.initials: R
authors.lastname: Pérez Calderón
authors.forename: D
authors.initials: D
authors.lastname: de Argila Fernández-Durán
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: Rangel Mayoral
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002121:Calcium Channel Blockers / Q000009:adverse effects*; D003429:Cross Reactions; D003873:Dermatitis, Exfoliative / Q000209:etiology; D004110:Diltiazem / Q000009:adverse effects*; D003875:Drug Eruptions / Q000209:etiology*; D004892:Erythema Multiforme / Q000209:etiology; D005076:Exanthema / Q000139:chemically induced; D005148:Facial Dermatoses / Q000139:chemically induced; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000009:adverse effects; D010328:Patch Tests; D011537:Pruritus / Q000209:etiology; D014700:Verapamil / Q000009:adverse effects*
chemical_list: D002121:Calcium Channel Blockers; D014700:Verapamil; D004110:Diltiazem; D009543:Nifedipine