All my clinical friends as well as people who have had serious illness or pregnancy probably know what it is. Anagen, Catagen and Telogen are the three phases of a hair’s growth cycle. In anagen, the hair is actively growing. In catagen, a hair has entered a resting phase and is no longer growing. In telogen, a hair falls out of its follicle – it winds up snarled in your comb or brush, or in the sink, or on the floor. I hate it when that happens.
When we experience a severe physiological stress such as surgery, a severe illness, or pregnancy, anagen phase hairs prematurely enter the telogen phase. While just a few percent of our hairs are normally in telogen phase, these stressors send a large portion of our hairs into telogen phase. Hence, a month or two after the stressful event, hairs start falling out at an alarming rate. This lasts a few months, and then hair typically grows back normally.
Not so differently, harsh environmental conditions such as drought or severe freezes have a similar effect on many trees. Here is my Monterrey Oak tree after last month’s hard freeze. Yesterday, I bagged as many leaves as you see here on the deck this afternoon. I expect that the tree will shed many more bags worth of leaves before new growth replaces the leaves that have been lost. Sigh.
