Clinical Experience
IgE-mediated reactionsHayfever and asthma occur through exposure to the pollen (3,6-9). Rhinitis and asthma have been described in wood workers exposed to Acacia wood (10).
A study reviewed perennial and seasonal aeroallergen trends in the Middle East, and their effect on military personal serving in the region. It was reported that most of the countries have significant grass and weed pollen seasons from April to May and from September to October, respectively. Indigenous trees such as Date palm, Acacia, and Mesquite have specific pollen seasons during various periods anywhere from March through May. Mould allergens were perennial, with seasonal peaks, whereas House dust mite was common in humid coastal regions. The study concluded that seasonal and perennial allergens observed in the United States are also found in the Middle East (11). In an earlier study of 327 adult patients with diseases of suspected allergic origin who were examined in a hospital in the United Arab Emirates, skin prick testing showed that among the 244 patients (74.6%) with positive results, Acacia was positive in 25.6% (12). In a study of aeroallergens in sandstorm dust investigated in Riyadh, Saudi Arabia, the most abundant aeroallergens were, among others, Acacia,
Alternaria,
Aspergillus and Bermuda grass (13). In a study in Saudi Arabia, of 1,159 patients tested for sensitisation to inhalants, Acacia was positive in 29% (7).
In a Malaysian study of asthmatic patients with and without rhinitis, 7.9% were skin-prick-test-positive to
Acacia spp. (14). In an earlier study in Kuala Lumpur, Malaysia, of 200 patients with asthma, 21.5% were sensitised to Acacia and 7.5% to
Melaleuca pollen. In pollen collection, grass and Acacia pollen grains were the 2 most commonly found pollens (15). In Montpellier, in southern France, Acacia resulted in positive skin prick tests, though the pollen was almost absent from pollen counts (8). Studies have demonstrated sensitisation to other Acacia species, including to Cootamundra wattle (
A. baileyana) along the Adriatic coast (16),
A. auriculiformis in West Bengal, India (17), and in Thailand, where pollen from this tree was shown to result in vernal keratoconjunctivitis (18). An earlier study reported that of 100 Thai individuals with allergic rhinitis, 19% were skin-prick-positive for Acacia (6).
Among 107 patients with allergic rhinitis and/or asthma in Jakarta, Indonesia, 12.15% were shown to be sensitised to
A. auriculiformis (19). Sensitisation to Acacia species was also demonstrated in Otaru, Japan (20). Occupational asthma has been reported due to Acacia species (21), and specifically to Blackwood (
A. Melanoxylon) (22).
A. Melanoxylon was also reported to cause occupational airborne contact dermatitis (23). Pollen from Sydney golden or the Mimosa tree (A. floribunda) was reported to be an occupational allergen in florists (24).
Compiled by Dr Harris Steinman,
harris@zingsolutions.com