Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Vancouver office at 604.283.9299
We will continue our discussion of how hair follicles change during the course of androgenetic alopecia (male pattern balding and female androgenetic alopecia). In general, hair follicles become thinner during the course of genetic hair loss. Before the onset of hair loss, most hairs in the scalp are thicker "terminal" hairs. These are typically 60 to 80 micrometers in diameter. During the thinning process, terminal hairs become "miniaturized" hairs and eventually "miniaturized" hairs become "vellus" hairs. Vellus hairs are always less than 30 micrometers in diameters. During the course of balding, terminal hairs become less common and vellus hairs become more common. During advanced balding, vellus hairs outnumber terminal hairs in the areas of balding. In such a case, we say that the terminal to vellus ratio (T:V) ratio is much less than 1:2.
Methotrexate is sometimes used as a treatment for children with alopecia areata. Generally, topical steroids, minoxidil are used first followed sometimes by diphencyprone (DPCP) and/or anthralin as second line agents. Methotrexate in my clinic tends to be a third line agent but in some situations I will use it before DPCP and anthralin.
Methotrexate is an immunosuppressant. It inhibits the proliferating of rapidly dividing immune system cells. Studies of children aged 8-18 years with alopecia areata have suggested that benefit is seen in about 40 % of children who use methotrexate.
The dose of methotrexate is discussed on a case by case basis. Generally, the dose to use depends on the child's weight. Doses in the range of 0.2 to 0.7 mg of methotrexate for every kilogram of body weight are not uncommon. The medication is only given once per week, and must never be used daily.
I generally start with 2.5 - 5 mg and slowly move upwards every week until the desired dose is obtained. For example, for a 70 pound child (31.8 kg), the dose range is 6.36 mg to 22.2 mg. I would generally start 2.5 mg in the first week and then 5 mg in the second week and then 10 mg in the third week and then 15 mg in the fourth week. One can move up faster if they wish, but this is my preference, especially in children under 10 years of age.
Many children tolerate methotrexate well. Nausea is the most common side effect and tends to occur on the particular day of the week that the medication is taken (methotrexate is not used every day). Sometimes vomiting can occur. Other side effects include lowered blood counts, irritation of the liver, and cough from irritation of the lungs.
I try hard to reduce nausea and especially vomiting in children taking methotrexate. Sometimes when children develop vomiting from Methotrexate then become extremely fearful of taking the medication. Administration of anti-nausea medications before taking the methotrexate can really help. About 25-30 % of children will have significant nausea with their methotrexate and 10 % will experience vomiting.
Folic acid is a vitamin which is prescribed every day except on the day that the child takes the methotrexate pill. The use of folic acid has been shown to reduce the chances of the child having changes in his or her blood counts and reduces the chance of the medication irritating the liver.
Royer M, et al. Efficacy and tolerability of methotrexate in severe childhood alopecia areata. Br J Dermal 2011;165(2):407-10.
Telogen effluvium (TE) and androgenetic alopecia (AGA) are common, especially among women. There are many ways to differentiate a shedding disorder (TE) from AGA - and some women have both.
A clinical examination of the scalp, a biopsy and a so called "hair collection" are three methods to evaluate a patient's diagnosis. Exactly which one I use depends on the specific clinical situation. Certainly not everyone with hair loss needs a biopsy and not everyone needs to perform a hair collection.
There are many different ways to perform a hair collection. Rebora studied the use of the 5 day hair collection, where shampooed hairs are trapped on a gauze 5 days after shampooing. The collected hairs are divided into three groups: telogen vellus hairs (less than 3 cm), intermediate hairs (3-5 cm) and long hairs (more than 5 cm). The presence of more than 10 % non broken hairs 3 cm or less is suggestive of the diagnosis of androgenetic alopecia (AGA).
Distinguishing androgenetic alopecia from chronic telogen effluvium when associated in the same patient: a simple noninvasive method.
Rebora A, et al. Arch Dermatol. 2005.