Cutaneous reactions due to diltiazem and cross reactivity with other calcium channel blockers

Contact dermatitis caused by diltiazem cream and cross‐reactivity with other calcium channel blockers

“…The second individual showed positive reactions to diltiazem and verapamil (30% pet. ), whereas the third patient showed no cross‐reactivity . Two other case reports have described cross‐reactivity in patch testing between diltiazem (10% or 30% pet.)…”

“…There are more publications reporting cutaneous side‐effects after oral intake of diltiazem than cutaneous side‐effects after topical application . However, exclusively anecdotical observations have been published on cross‐reactivity of the pharmacologically different CCBs after oral intake.…”

“…However, exclusively anecdotical observations have been published on cross‐reactivity of the pharmacologically different CCBs after oral intake. Some authors reported recurrent cutaneous reactions after oral administration even of different classes of CCB, whereas a switch to a different CCB was well tolerated in another patient …”

Photoallergic dermatitis induced by diltiazem

“…Epicutaneous patch tests are useful for reinforcing the diagnosis of cutaneous adverse reactions to this drug (8–10). They are mainly performed with diltiazem “as is” preparations, diltiazem at 1%, 5%, 10%, 20%, and 30% in petrolatum preparations, diltiazem at 5%, 10%, 20%, and 30% in water preparations, and diltiazem at 30% in alcohol preparations (8–10).…”

“…Given the fact that in some instances the cutaneous lesions do not clinically improve after replacing the suspected calcium channel antagonist with a different one, cross‐reactions among these drugs are being considered (9, 10). Cholez et al divided calcium channel inhibitors into two main groups: dihydropirydines (nifedipine) and no‐dihydropirydines (verapamil and diltiazem) and considered cross‐reactions among drugs from different groups to be uncommon (9).…”