Photodynamic therapy for the treatment of hair loss

Abstract

Photodynamic therapy (PDT) is used to stimulate and/or restore hair growth in areas of hair loss. Methods and compositions relating to PDT treatment for alopecia are disclosed. In light of PDT use to remove unwanted hair by inactivating or destroying hair follicles or destroying the tissue feeding the hair follicles, such methods and compositions relate to a surprising and unexpected discovery. PDT permits a means to treat conditions relating to hair loss such as androgenic alopecia, alopecia areata and drug-induced alopecia.

1 . A pharmaceutical composition to treat, prevent, or inhibit the development of, hair growth reduction or hair loss, said composition comprising an effective amount of photosensitizer and a pharmaceutically acceptable carrier or excipient for directing the photosensitizer to the sites of hair growth reduction or hair loss.  
     
     
         2 . A method of preparing an area of skin for photodynamic therapy to increase the number of terminal hairs in said area, said method comprising administering the pharmaceutical composition of  claim 1  to said area.  
     
     
         3 . A method of preparing an area of skin for photodynamic therapy to treat androgenetic alopecia, said method comprising administering the pharmaceutical composition of  claim 1  to said area.  
     
     
         4 . A method of determining the increase in hair growth in a subject's skin exhibiting hair growth reduction or hair loss, said method comprising 
 a) administering a photosensitizer to said skin;    b) irradiating said skin with electromagnetic energy containing a wavelength absorbed by said photosensitizer to activate it; and    c) measuring the increase in hair growth,    wherein an increase in hair growth in comparison to skin that has not been treated with both a) and b) can be determined.    
     
     
         5 . The method of  claim 4  wherein said photosensitizer is one which absorbs activating radiation in the range of about 400 nm to about 800 nm.  
     
     
         6 . The method of  claim 4  wherein said administering is by topical application.  
     
     
         7 . The method of  claim 4  wherein said electromagnetic energy is visible light.  
     
     
         8 . The method of  claim 4 , wherein said skin that has not been treated has not been administered said photosensitizer.  
     
     
         9 . The method of  claim 4 , wherein said skin that has not been treated has not been irradiated.  
     
     
         10 . The method of  claim 4 , wherein said measuring is selected from counting the number of terminal hairs, measuring hair weight, measuring hair density, and/or measuring hair shaft diameter.