As the symptoms of a food allergy are so varied it can make it difficult to detect and diagnose a food allergy. The following list provides an extensive breakdown of complaints caused by food allergies. However, it is important to note that many of these symptoms can be caused by other diseases and you need to be sure these have been ruled out before deciding that a food allergy is the cause.

- Abdominal pains
- Alcoholism or cravings for foods, tobacco, drugs; bingeing; constant hunger; nausea
- Asthma; breathing difficulty
- Bloating or discomfort after food; bowel cramps; colic; wind; heartburn or indigestion
- Bruising
- Chest pains
- Dizziness; violence, rage; melancholy
- Epilepsy
- Excessive sweating; night sweats; sudden "chill" or "hots
- Extra sensitivity to touch in some places
- Fatigue or tiredness not helped by rest; lethargy; sleepiness after eating
- Feelings of confusion; forgetfulness; periods of poor concentration; inability to think clearly
- Flu-like symptoms
- Fluid retention; puffy face, eyes, hands, legs, ankles; overweight or underweight, obesity
- Frequent cystitis
- Glue ear
- Headaches and migraines
- Hypractivity or restlessness
- Hyperactivity in children
- Hypoglycaemia
- Irritability; mood swings; depression; nervous tension, anxiety, fear
- Irritable bowel syndrome; constipation; diarrhoea; anal itching
- Itch - with or without a skin rash; blotches or hives (nettle rash); eczema
- Learning difficulties
- Loss of confidence; feelings of detachment or unreality, of being an "onlooker"
- Mild fever
- Mouth ulcers; bad breath
- Muscle weakness or general weakness
- Numbness; tingling or burning sensation
- Racing or fluttering pulse; palpitations
- Rheumatism; aching muscles; stiff neck; arthritis; stiff or painful joints; backache; face ache or face tenderness
- Ringing or whistling in the ears (tinnitis); repeated ear infections in children; flutuating deafness
- Sleep disturbance
- Sneezing or itchy nose; runny nose; watery eyes; blocked or inflamed sinuses; mouth breathing or snoring
- Swelling of tongue, mouth, lips
- Swollen or tender glands
- Vaginal discharge; menstrual disorders

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