Formaldehyde skin allergies

Formic acid is readily metabolized and eliminated by the body. Nonetheless, it has specific toxic effects the formic acid and formaldehyde produced as metabolites of methanol are responsible for the optic nerve damage, causing blindness seen in methanol poisoning. Some chronic effects of formic acid exposure have been documented. Some animal experiments have demonstrated it to be a mutagen, and chronic exposure may cause liver or kidney damage. Another effect of chronic exposure is development of a skin allergy that manifests upon re-exposure to the chemical. 

Eberlein-Konig B, Przybilla B, Kuhnl P, et al. 1998. Influence of airborne nitrogen dioxide or formaldehyde on parameters of skin function and cellular activation in patients with atopic eczema and control subjects. J Allergy Clin Immunol 101 141-143. 

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