These answers are for informational purposes and do not replace a physician head-to-head visit. A patient-physician relationship is not established.
Thank you for asking your interesting questin.
Lichen planopilaris is a condition of unknown etiology, though some sort of autoreaction ( though not generally categorized in the autoimmune disease group) in which lympohcytes attack and ultimately destroy the hair follicle. Thus, it is placed in the scarring alopecia group. It is generally marked by perifollicular erythema and scaling. One will find groups of follicular papules.
As far as I know it does not have a hereditary component.
LPP typically affects middle aged women. Some authorities question whether it should be separated from lichen planus, though about 30% of patients with LPP also have lichen planus elsewhere.
I am not sure if you are interested in the latest theory regarding its pathophysiology, but there seems to be a down-regulation of peroxisome proliferator-activated receptor gamma. This causes an abnormality in both the sebaceous glands and cell immunity. Curiously, the drug Actos and its family up-regulates PPAR. I have used this twice on tear filled women who were suffering from LPP. Both times successfully, but, of course, I risked the wrath of the lawyers due to Actos's link with bladder cancer. However, I had two very grateful patients.
A biopsy is really needed to confirm the diagnosis: a 4 mm punch biopsy that goes deep enough into the sub-cutaneous tissue. It is important to obtain the biopsy from an active area, and not one that is already scarred.
The main differential is between LPP, and pseudopelade of Bracq ( "footsteps in the snow"), discoid lupus, and central centrifugal cicatricial alopecia. Many authorities consider frontal fibrosing alopecia a form of LPP.
The anterior scalp is the most common site, but other areas may be involved. Looks for the erythematous papules around the hair follicle and a keratotic plug. The periphery of the region is most involved as this is the active "border". With discoid lupus the central area is most affected: in PLL the periphery. Those are the aras you want to treat with injections.
Some cases resolve,eith treatment or without and others go on to total heir loss. Unfortunately, we dermatologists usually see patients at the end of the process when there is not much to do but stare at a bald scap.
I sually use intralesional steroids and if this does not work, I add Plaquanil and Doxycycline, both rather safe medications.
I have read about the use of Cell-Cept for LPP but have personally never tried it. Neoral is also used, but again, I have never tried that one either.
I would be happy to answer further questions or elaborate on the above. Just let me know.
Many thanks for your comprehensive reply. My patient's story was that her sister developed a cancerous growth. While her sister was undergoing treatment my patient suddenly lost her hair..?alopecia areata? The hair grew back patchily and she had a biopsy which gave this diagnosis. A further analysis is awaited. She is only 23 years old and wanted to know if her offspring would be affected, once she marries. The pathologist considered "folliculotropic mycosis fungoides" as a possibility. Any comment? Thank you.
This really is not behaving like Lichen planopilaris. It would worthwhile to repeast the bipsy and ask the pathologist for clonal studies ( PCR or Western blot) to see whether the lymphocytes are from the same clone. This would differentiate tumor from inflammatory.