We all know about pattern baldness and alopecia in terms of hair loss, but what do you know about drug-induced hair loss? Chemotherapy is a common and well-known cause of hair loss, but did you know hundreds of medications used for different conditions also cause hair loss?
The Hair Cycle
First, we need to understand how the hair cycle works. Is it normal for men and women to experience hair loss? Hair on the scalp grows an average of 0.3 to 0.4 mm a day. At any given time, many hairs will be in one of three stages of growth and shedding:
Anagen is the active phase of the hair growth cycle. The cells in the root of the hairs are dividing rapidly. A new hair is formed and pushes the club hair (a hair that has stopped growing or is no longer in the anagen phase) up the follicle and eventually out. This phase lasts an average of 2 to 7 years.
The catagen phase is a transitional stage. About 3% of all hairs are in this phase at any time, lasting around 2 to 3 weeks. Growth will stop, and the outer root sheath shrinks and attaches to the root of the hair; this is the formation of what is known as ‘club hair.’
Telogen is the resting phase of hair growth and usually accounts for 6% to 8% of all hairs. This phase lasts around 100 days for hairs on the scalp. The hair follicle is totally at rest during this phase, and the club hair is formed completely. It is entirely normal to lose an average of 50 to 100 telogen hairs each day. These shedding stages are perfectly normal and are nothing to be concerned about. This phase lasts around 3 months.
Types of Hair Loss
Medications can lead to one of two types of hair loss. The severity of drug-induced hair loss depends on the types of medication been taken, the dosage, and the person’s sensitivity to that drug.
Telogen effluvium is the most common way hair loss occurs through medications and usually appears 2 to 4 months after starting the medications. The condition causes the hair follicles to go into a resting phase leading to premature shedding of 30% to 70% more hair than usual.
This type of hair loss occurs during the anagen phase. It prevents the ‘matrix cells’ (part of the hair follicle where matrix keratinocytes multiply rapidly to form the hair shaft of growing hair) from diving normally. Anagen effluvium can happen days or weeks after you first start taking the medication. This type of hair loss is most common in those undergoing chemotherapy.
Types of Medications That Can Induce Hair Loss
- Acne medications containing vitamin A (retinoids)
- Antibiotics and antifungal drugs
- Birth control pills
- Anticlotting drugs
- Cholesterol-lowering drugs
- Drugs that suppress the immune system
- Drugs that treat breast cancer and other cancers
- Epilepsy drugs (anticonvulsants)
- High blood pressure medications (anti-hypertensives), such as beta-blockers, ACE inhibitors, and diuretics
- Hormone replacement therapy
- Mood stabilizers
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Parkinson’s disease drugs
- Thyroid medications
- Weight loss drugs
Treating Drug-Induced Hair Loss
With most medications, if you stop taking them, the hair should grow back. If this is not the case, then there are a couple of medications you can take that will help to either slow the hair loss process down or stimulate new hair growth.
- Finasteride (Propecia)
- Minoxidil (Rogaine)
In some cases, scalp micropigmentation (SMP) can help. Rather than being completely bald until you reach sufficient hair growth, SMP can help you disguise the hair loss by giving you the appearance of a full head of shaved hair. Or SMP can conceal the areas of the scalp that have suffered some hair loss without you having to shave the remaining hair.