Formaldehyde is a chemical agent found in virtually all homes and workplaces. In addition to acting as a contact allergen, inhalation of formaldehyde can exacerbate asthma.

Nature

Formaldehyde is a low-molecular weight organic chemical (1), used in industrial and commercial settings as a solution, disinfectant, preservative, and resin (2), and in household settings as foam insulation, in cleaning and personal care products, textiles, dishwashing liquids and in pressed wood products (2-4). It is present in virtually all homes and workplaces (Lam et al, 2021). As such, formaldehyde is a common contact allergen (3) that, in addition to being an irritant, is also an allergen acting as a hapten (1).

Some products that do not contain formaldehyde still contain substances that release formaldehyde as they break down (4). These are known as formaldehyde releasers and can independently cause contact allergic dermatitis (4).

Worldwide distribution 

Formaldehyde exposure is widespread in homes, communities, and workplaces (2). In Denmark over a ten-year period (2007–2016), the prevalence of contact allergy to formaldehyde 1% was found to be 1.5%, while contact allergy to formaldehyde 2% was found to be 2.4% (5). Among patients referred for allergic contact dermatitis to an American medical center, 8.1% were allergic to formaldehyde, 7.1% were allergic to Bioban™ (a cleaning chemical), and 9.5% were allergic to other formaldehyde releasers (6).

In Finland, formaldehyde and formaldehyde releasers caused 5.5% of cases of occupational allergic contact dermatitis during the period from 2005–2016 (7).

Risk factors 

Occupational contact allergic dermatitis is seen in many professions, including manual labor and professional occupations (8).

Low-income communities are disproportionately exposed to formaldehyde; the use of low-cost building materials, including pressed wood products, puts inhabitants at an increased risk of formaldehyde exposure (2).

Main 

Contact (3).

Secondary

Inhalation (2).

Allergic contact dermatitis in formaldehyde-sensitized patients is often chronic due to the ubiquitous nature of formaldehyde, and frequently presents on the hands and face where contact is most likely (4).

In addition to contact allergies, inhalation of formaldehyde is a potential cause of asthma, where exposure occurs primarily through inhalation, but also occurs by direct contact irritation of the respiratory tract (2).

Author: RubyDuke Communications

Reviewer: Dr. Christian  Fischer 

Last reviewed: April 2022