Formaldehyde‐induced urticarial vasculitis

Abstract

A 40-year-old male medical student presented with urticarial vasculitis secondary to occupational formaldehyde exposure. Serum sickness and delayed pressure urticaria also featured prominently during his illness. Initial symptom control was achieved with oral prednisolone (25 mg/day tapered to zero over 2 weeks) and oral antihistamine therapy (fexofenadine 180 mg once daily, promethazine 20 mg once daily, ranitidine 150 mg twice daily); however, subsequent exposures to formaldehyde produced transient symptom flares that broke through the prednisolone cover. A complete recovery occurred only after strict elimination of all exposure to formaldehyde, both occupationally and in the home environment, was achieved.

Urticarial lesions: If not urticaria, what else? The differential diagnosis of urticaria

“…One such stimulus may be drugs, including antifolate agents (methotrexate and pemethrexate), 26,27 antidepressants (paroxetine and fluoxetine), 28,29 appetite suppressants, 30 infliximab, 31 procainamide, 32 cimetidine, 33 sulfamethoxazole-trimethoprime, 34 and other substances (herbs, cocaine, bacillus Calmette-Guérin vaccine, and formaldehyde). [35][36][37][38] Moreover, rare cases induced or exacerbated by physical stimuli have been reported, including sun or ultraviolet light exposure, 39,40 cold, 41,42 and physical exercise. 43 In some UV patients, a collagen-like region of the complement fragment C1q has been implicated as the target antigen.…”