Types of Hair Loss and Treatment Options, Including the Novel Low-level Light Therapy and its Proposed Mechanism

Mahyar Ghanaat, MD

Disclosures

South Med J. 2010;103(9):917-921. 

In This Article

Traditional Treatment Options

The two medications approved for MPHL by the United States Food and Drug Administration (FDA) are 5% minoxidil and finasteride.[2,3,19] Two percent minoxidil is the only approved medication for FPHL.[3,10] Minoxidil is an antihypertensive medication with peripheral vasodilator properties, and the side effect when taken systemically is hypertrichosis.[1,11] After application, minoxidil is converted to minoxidil sulfate, a potassium channel opener which relaxes vascular smooth muscle and increases blood flow.[6] It was first suspected that this increased blood flow is the mechanism by which minoxidil affects hair loss, but this may not be the case.[11] In vitro studies of hair growth have shown that hair cultures grown in the presence of minoxidil maintain morphology, whereas controls undergo kinking and necrosis.[21] A common side effect of minoxidil is contact dermatitis, which can initially be managed by switching to a 2% solution or the foam preparation, which lacks propylene glycol (an irritating substance).[2] Corticosteroids may also be beneficial to improve pruritic side effects.[11] One drawback with minoxidil treatment is that it requires twice daily application indefinitely to maintain results.[1,2,6] Shin et al[6] have proposed that combination of minoxidil with tretinoin once a day makes no significant difference in efficacy or side effect profile (as opposed to minoxidil twice a day), and may improve patient compliance. Tretinoin increases the absorption of minoxidil.[6] Two percent minoxidil is approved for women, as studies have shown the same efficacy with the 5% solution, yet a higher rate of hypertrichosis with topical application.[8,19] Minoxidil is effective in adolescents.[12]

Finasteride is an oral agent, which is a competitive 5-AR inhibitor with more affinity for Type II 5-AR.[8,11,13] Thus, it inhibits the conversion of T to its more active form of DHT.[2,4] Given its systemic nature, potential side effects of finasteride include erectile dysfunction, gynecomastia, and loss of libido.[1] Like minoxidil, this is an ongoing therapy. Finasteride is only approved for men 18 years of age or older.[12]

Whereas minoxidil and finasteride are temporizing measurements and require continuous administration, hair restoration may serve as a definitive treatment.[2,9] This procedure is based on the fact that occipital hair follicles are not androgen dependent, and that transplanted hair maintains donor dominance.[9,22] Follicular units are acquired from the occipital scalp and transplanted into the frontal scalp in a cosmetically acceptable manner.[9,22] This procedure should ideally be performed on individuals who have reached a plateau in balding and have realistic expectations.[9,22] Side effects are usually minor and include postoperative pain, delayed hair growth, and, rarely, infection.[9] Periorbital and frontal swelling may also occur.[22] Some argue that the future procedure of hair cloning may dramatically improve this process.[23]

In addition, there are a variety of off-label and investigational drugs that are used or considered in the treatment of hair loss. Dutasteride is a dual Type I and II 5-AR inhibitor.[4,7] Latanoprost is a prostaglandin mainly used for glaucoma, which was observed to stimulate eyelash and eyebrow growth.[7] The antifungal agent ketoconazole may also promote hair growth, perhaps by inhibiting inflammation and serving as an antiandrogen.[7] Other investigational drugs include fluridil, a topical antiandrogen; naminidil, which works through the potassium (K) channel; P-45, which may inhibit interleukin 4 (I-L4)-induced CD23 expression; PSK 3841, a topical nonsteroidal androgen antagonist; and lemuteporfin (QLT 0074), a photosensitizer to be used with photodynamic therapy.[3] Other agents include antiandrogen oligonucleotides—which are deoxyribonucleic acid (DNA) that pairs with complementary ribonucleic acid (RNA)—KF19418, LGD1331, steroid sulfatase inhibitors, and thymosin beta 4, which stimulates hair growth via stem cell migration.[3] Gene delivery through liposome technology has also showed some success.[3]

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