Internal disease. Please see your doctor for an evaluation. Thyroid disease is one possibility but there are other hormonal problems that could be causing this.
Malnourished. Lanugo is the growth of fine hair "peach fuzz" it is the body attempt to insulate to trap and retain heat, when there is insufficient body fat. This can be seen in people with eating disorders, like anorexia. This is a sign of being severely malnourished, from any cause. And can be seen in people with eating disorders like anorexia.