1.Lagna ( ascendant lord ) weak , badly placed ,afflicted or under malefic aspect.
2. Sixth lord in conjunction/relation with 1st, 8th or 12th lord and under malefic aspect.
3.Mercury com-bust,retrograde badly placed ,afflicted or under malefic aspect.
4.Jupiter and Venus weak ,badly placed or under malefic aspect.
5. Moon/Venus or both under malefic aspect.
6.Weak Luminaries. ( sun and moon)
7.Saturn and mars in opposition.
8.Rahu,Saturn,jupiter are vata planets and effect lower part of body.
9.Sun and Mars are pitta or heat generating planets and effect middle part of body
10.Moon,venus are kapha planets and effect upper part of body .
11. Mercury signifies all three doshas and thus it signifies immune system.