Formaldehyde

Question 2

Rates of Formaldehyde Positivity

Answer 2

Some investigators have stated that 75% of positive patch tests have no clinical significance and only 20% of these can be related to actual instances of formaldehyde dermatitis.

Question 3

How is formaldehyde patch tested?

Answer 3

2% aqueous solution of formalin

Question 4

Formaldehyde clothing dermatitis — what criteria needs to be met?

Answer 4

Suspected fabric shows the presence of free formaldehyde

The patient shows a positive patch test reaction to 2% formalin

Formaldehyde resin impregnated fabric show a positive patch test reaction — the piece of fabric tested should have been worn and subjected to sweat, sebum and friction

Wearing the fabric causes a clinical allergic contact dermatitis.

Question 5

How do you avoid formaldehyde?

Answer 5

It is difficult to avoid all exposure to formaldehyde because it is normally present at low levels (usually <0.03 ppm) in both indoor and outdoor air. For most people, low-level exposure (up to 0.1 ppm) does not cause any problems.

Methods to avoid or minimise exposure to high levels of formaldehyde:

• Wear clothing made of 100% cotton, silk, polyester, nylon or acrylic; these fabrics generally contain less formaldehyde and are usually well tolerated by sensitive individuals
• Avoid all clothing made with fabrics that have been treated with formaldehyde (see above)
• In general, machine wash all new clothing and bedding in hot, soapy water several times before use
• Purchase furniture made of pressed wood products only if the surfaces and edges are laminated or coated
• Occupational exposure can be reduced by identifying potential sources of exposure (material safety data sheets should be available to employees) and taking precautions to minimise exposure by wearing suitable protective garments
• To reduce the formaldehyde content in the air, increase ventilation by opening doors and windows and installing exhaust fans in closed areas

Read product labels and avoid not only formaldehyde itself but also formaldehyde-releasing preservatives. Some of these are known by the following names:
* Quaternium-15
* 2-bromo-2-nitropropane-1,3-diol (bronopol)
* Imidazolidinyl urea
* Diazolidinyl urea