Hypersensitivity to lipid transfer protein is frequently associated with chronic urticaria

Sparse clinical observations suggest a possible association between food allergy to lipid transfer protein (LTP) and chronic urticaria (CU).

To investigate the possible association between LTP hypersensitivity and CU.

History of CU, and/or of NSAID hypersensitivity was prospectively assessed in 75 consecutive LTP-allergic subjects (M/F 27/48; age 33.6 years); those with positive histories underwent an autologous serum skin test (ASST). 100 atopic subjects not sensitized to LTP and 100 subjects with chronic urticaria served as controls.

16/75 (21%) patients had a history of current or past CU. 7 (9%) had a history of NSAID-induced urticaria, and the ASST scored positive in 9/11 patients (82%). By comparison with atopic controls patients showed a significantly higher prevalence of CU (21% vs 6%; p < 0.01), a > 4 times more frequent history of NSAID hypersensitivity (9% vs 2%), and a higher prevalence of females (p< 0.05). In contrast, patients and controls with chronic urticaria showed a similar sex distribution, prevalence of positive ASST, and prevalence of NSAID hypersensitivity.

An unidirectional association between LTP hypersensitivity and chronic urticaria seems to exist. The reasons for this are unclear although it is possible that CU makes mast cells more easily excitable by food allergens. Further, it has been shown that NSAIDs may up-regulate type 1 allergic responses to foods, possibly increasing permeability of the gut mucosa.