1. because the disease is chronic, its severity fluctuates and sometimes there may be prolonged remissions i.e. in between attacks there may be no signs,no symptoms, no positive laboratory tests, which may be the cause in your case.
2. Environmental pollution is one of the contributory factor for repeated attacks, make sure you take adequate measures against the same.
3. In Ayurveda we consider such symptoms under "Jeerna Pratishyaya" so use of medicines like lakshmi vilas ras, vasaavleha, chitrak haritki, shring bhasm, sitopladi churna for a period of 6-8 months will help you in getting relief from your symptoms.
4. Avoid: heavy-cold-constipating food, curd,mustard oil,excess of physical exertion-exposure to sun-dust,day time sleeping,dairy products, wheat, sugar,potatoes, tomatoes,peppers, bananas,oranges, grapefruits.
5. take raw turmeric+ raw ginger: 2gm each and fry in 6 gm of cow ghee, and add 6 gm jaggery to it and take with milk at bed time, alternatively use shadbindu oil in your nostrils for some time.
6. Rasayan chikitsa (immunomodulation) should be initiated to prevent recurrence like guduchi,Ashwagandha