Psoriasiform Contact Dermatitis Responding to High-Dose Folic Acid

We report a case of allergic contact dermatitis in a patch tested area with histopathologic examination showing psoriasiform dermatitis with that and another area with the same histopathology clearing using only daily oral doses of 6 mg folic acid, 100 mg vitamin B6 and 100 mcg vitamin B12. We found a negative correlation coefficient of -0.82 in aggregate for all psoriasiform dermatitis areas proven by biopsy. On the same patient other areas when biopsied showed lichen simplex chronicus. These areas in aggregate showed negative correlation of body surface area involved of only -0.52 despite treatment including not only the administration of these vitamins but also intralesional and topical corticosteroids and other topical immune modulators. High dose folic acid appears to be a potential therapy for patients with allergic contact dermatitis though this may only be appropriate in patients with high BMI and with comorbid signs of psoriasis.