All are true about lymphedema except

Lymphoedema may be defined as abnormal limb swelling caused by the accumulation of increased amounts of high protein ISF secondary to defective lymphatic drainage in the presence of (near) normal net capillary filtration. At bih, 1 in 6000 people will develop lymphoedema with an overall prevalence of 0.13-2%.The severity of unilateral limb lymphoedema can be classified as:mild: <20% excess limb volume;moderate: 20-40% excess limb volume;severe: >40% excess limb volumeTypes of Primary lymphedemaCongenital (onset <2 years old): sporadic; familial (Nonne-Milroy's disease)Praecox (onset 2-35 years old): sporadic; familial (Letessier-Meige's disease)Tarda (onset after 35 years old)Ref: Bailey and love 27e pg: 998