Contact Dermatitis
Adverse skin reactions have been reported frequently among workers who have direct contact with rubber and with the hundreds of chemicals used in the rubber industry. These reactions include irritant contact dermatitis, allergic contact dermatitis, contact urticaria (hives), aggravation of pre-existing skin diseases and other less common skin disorders such as oil folliculitis, xerosis (dry skin), miliaria (heat rash) and depigmentation from certain phenol derivatives.
Irritant contact dermatitis is the most frequent reaction and is caused by either acute exposure to strong chemicals or by cumulative exposure to weaker irritants such as those found in wet work and in repeated use of solvents. Allergic contact dermatitis is a delayed type of allergic reaction from the accelerators, vulcanizers, anti-oxidants and anti-ozonants which are added during rubber manufacture. These chemicals are often present in the final product and may cause contact dermatitis in both the end-product user as well as in rubber workers, especially Banbury, calender and extruder operators and assemblers.
Some workers acquire contact dermatitis through exposure in work which does not permit the use of chemical-protective clothing (CPC). Other workers also develop allergy to CPC itself, most commonly from rubber gloves. A valid positive patch test to the suspected allergen is the key medical test which is used to differentiate allergic contact dermatitis from irritant contact dermatitis. It is important to remember that allergic contact dermatitis may coexist with irritant contact dermatitis as well as with other skin disorders.
Dermatitis may be prevented by automated mixing and preblending of chemicals, provision of exhaust ventilation, substitution of known contact allergens with alternative chemicals and improved materials handling to reduce skin contact.
Natural Rubber Latex (NRL) Allergy
NRL allergy is an immunoglobulin E–mediated, immediate, Type I allergic reaction, most always due to NRL proteins present in medical and non-medical latex devices. The spectrum of clinical signs ranges from contact urticaria, generalized urticaria, allergic rhinitis (inflammation of nasal mucosa), allergic conjunctivitis, angio-oedema (severe swelling) and asthma (wheezing) to anaphylaxis (severe, life-threatening allergic reaction). Highest risk individuals are patients with spina bifida, health care workers and other workers with significant NRL exposure. Predisposing factors are hand eczema, allergic rhinitis, allergic conjunctivitis or asthma in individuals who frequently wear gloves, mucosal exposure to NRL and multiple surgical procedures. Fifteen deaths following NRL exposure during barium enema examinations have been reported to the US Food and Drug Administration. Thus the route of exposure to NRL proteins is important and includes direct contact with intact or inflamed skin and mucosal exposure, including inhalation, to NRL-containing glove powder, especially in medical facilities and in operating rooms. As a result, NRL allergy is a major worldwide medical, occupational health, public health and regulatory problem, with the number of cases having increased dramatically since the mid-1980s.
Diagnosis of NRL allergy is strongly suggested if there is a history of angio-oedema of the lips when inflating balloons and/or itching, burning, urticaria or anaphylaxis when donning gloves, undergoing surgical, medical and dental procedures or following exposure to condoms or other NRL devices. Diagnosis is confirmed by either a positive wear or use test with NRL gloves, a valid positive intracutaneous prick test to NRL or a positive RAST (radioallergosorbent test) blood test for latex allergy. Severe allergic reactions have occurred from prick and wear tests; epinephrine and resuscitation equipment free of NRL should be available during these procedures.
NRL allergy may be associated with allergic reactions to fruit, especially bananas, chestnuts and avocados. Hyposensitization to NRL is not yet possible, and NRL avoidance and substitution is imperative. Prevention and control of NRL allergy includes latex avoidance in health care settings for affected workers and patients. Substitute synthetic non-NRL gloves should be available, and in many cases low-allergen NRL gloves should be worn by co-workers to accommodate those with NRL allergy, in order to minimize symptoms and to decrease induction of NRL allergy. Continued cooperation among government, industry and health care professionals is necessary to control latex allergy, as discussed in the Health care facilities chapter.