出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/09 17:20:10」(JST)
| It has been suggested that this article be merged with Balanitis xerotica obliterans. (Discuss) Proposed since January 2015. |
| Lichen sclerosus | |
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Micrograph of lichen sclerosus showing the characteristic subepithelial sclerosus (right/bottom of image). H&E stain.
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| Classification and external resources | |
| Specialty | dermatology |
| ICD-10 | L90.0 |
| ICD-9-CM | 701.0 |
| eMedicine | derm/234 |
| MeSH | D018459 |
Lichen sclerosus (LS) (also termed, incorrectly, "Lichen sclerosus et atrophicus"[1]:227) is a disease of unknown cause that results in white patches on the skin, which may cause scarring on and around genital skin.[2] There is a bimodal age distribution in the incidence of LS. It occurs in girls with an average age of diagnosis of 7.6 years in girls and 60 years old in women. The average age of diagnosis in boys is 9–11 years old.[3]
Several risk factors have been proposed, including autoimmune diseases, infections and genetic predisposition.[4][5] There is evidence that LS can be associated with thyroid disease.[6]
Women are more commonly affected than men (10 to 1 ratio), particularly around and after menopause, but younger women or girls may also develop the disease. The condition most commonly occurs on the vulva and around the anus with ivory-white elevations that may be flat and glistening. There may be marked itching or the condition may be without any symptoms. There may also be thinning and shrinkage of the genital area that may make coitus, urination, and defecation painful.
In males, the disease may take the form of whitish thickening of the foreskin, which cannot be retracted easily (phimosis). In contrast to women, there is no perianal involvement. In men, this genital involvement has traditionally been known as balanitis xerotica obliterans (BXO).[7]
Only 6% of LS are isolated extragenital lesions.[8] On the non-genital skin, the disease may manifest as porcelain-white spots with small visible plugs inside the orifices of hair follicles or sweat glands on the surface. Thinning of the skin may also occur.[9] [The appearance of the skin, as symptoms listed here, do not include those that may appear in members of some minority groups; I.E. "African-Americans", or others whose skin contains more melanin, may display skin symptoms that appear different than those described here, which would seem to be those that "whites" or Caucasians would most likely display.{Article may need editing to include symptoms displayed by a more diverse cross-section of suffers.}]
Although it is not clear what causes LS, several theories have been postulated. Lichen Sclerosus is not contagious; it cannot be caught from another person.[10]
Lichen sclerosus may have a genetic component. Higher rates of lichen sclerosus has been reported among twins [11][12] and families.[13]
Autoimmunity is a process in which the body fails to recognize itself and therefore attacks its own cells and tissue. Specific antibodies have been found in LS. Furthermore, there seems to be a higher prevalence of other autoimmune diseases such as diabetes mellitus type 1, vitiligo and thyroid disease.[14]
Both bacterial as well as viral pathogens have been implicated in the etiology of LS. A disease that is similar to LS, acrodermatitis chronica atrophicans is caused by the spirochete Borrelia burgdorferi. Viral involvement of HPV[15] and hepatitis C[16] are also suspected.
A link with Lyme Disease is shown by the presence of Borrelia burgdorferi in LSA biopsy tissue.[17]
Since LS in females is primarily found in women with a low estrogen state (prepubertal and postmenopausal women), hormonal influences were postulated. To date though, very little evidence has been found to support this theory.
Some findings suggest that LS can be initiated through scarring[18] or radiation,[19][20] although these findings were sporadic and very uncommon.
The disease often goes undiagnosed for several years, as it is sometimes not recognized and misdiagnosed as thrush or other problems and not correctly diagnosed until the patient is referred to a specialist when the problem does not clear up.
A biopsy of the affected skin is often done to confirm diagnosis. When a biopsy is done, hyperkeratosis, atrophic epidermis, sclerosis of dermis and lymphocyte activity in dermis are histological findings associated with LS.[21] The biopsies are also checked for signs of dysplasia.[22]
There is no definitive cure for LS.[23] Behavior change, such as good hygiene and minimizing scratching of the affected area, is an important part of treatment.[24] LS is also usually treated with potent topical steroids, like clobetasol propionate or mometasone furoate.[23] These can relieve symptoms and prevent scarring.[25] However, LS is a chronic disease so topical steroids may need to be continued as maintenance therapy.[24]
In cases of prepubertal LS, there is some evidence that patients can undergo remission of LS. In a cohort of 12 girls who followed up for 10 years until adolescence, 25% underwent complete remission. Unfortunately, 75% remained symptomatic and demonstrated physical signs of LS into adolescence.[26]
Other treatments including topical hormonal therapies (testosterone and progesterone) have been proposed but not conclusively proven to improve symptoms.[24] Another small study has shown long-term antibiotic treatment to be effective in patients who had poor response to steroids.[22]
It is not considered beneficial to remove LS-affected skin that is not located on the genitals, as it also tends to relapse.
In females, recent studies indicate that the injection of PRP (Platelet-rich plasma) and stem cells in site may reduce symptoms and improve lesions. The usefulness of this treatment in males is under study.[27]
In severe cases, chronic lichen sclerosus may cause anatomical changes, such as labial adhesions or vaginal agglutination, as a result of long-standing inflammation; surgery may be required in these instances.[24]
Recent studies indicate a role for topical calcineurin inhibitors such as tacrolimus.[28][29]
Distress due to the discomfort and pain of Lichen Sclerosus is normal, as are concerns with self-esteem and sex. Counseling can help. Patients suffering from painful intercourse may also benefit from using lubricants or moisturizers.[24]
According to the National Vulvodynia Association, which also supports women with Lichen Sclerosus, vulvo-vaginal conditions can cause feelings of isolation, hopelessness, low self-image, and much more. Some women are unable to continue working or have sexual relations, and may be limited in other physical activities.[30] Depression, anxiety, and even anger are all normal responses to the ongoing pain LS patients suffer from.
The disease can last for a considerably long time. Occasionally, "spontaneous cure" may ensue,[31] particularly in young girls.
Lichen sclerosus is associated with a higher risk of cancer.[32][33][34] Skin that has been scarred as a result of lichen sclerosus is more likely to develop skin cancer. Women with lichen sclerosus may develop vulvar carcinoma.[35] Lichen sclerosus is associated with 3-7% of all cases of vulvar squamous cell carcinoma.[36] Periodic consultation is therefore necessary.
Lichen sclerosus (LS) is also known as lichen sclerosus et atrophicus (LSA), balanitis xerotica obliterans (BXO), Csillag's disease, Lichen albus, Hypoplastic dystrophy, White Spot Disease and kraurosis vulvae. Typically it's called LSA or BXO when it affects men, LS when it affects women or in referring to the disease in general, and pediatric lichen sclerosus when it affects children. LS is usually found in the groin area, but sometimes on the upper leg or thigh.
Lichen sclerosus et atrophicus was first described in 1887 by Dr. Hallopeau.[37] Since not all cases of lichen sclerosus exhibit atrophic tissue, et atrophicus was dropped in 1976 by the International Society for the Study of Vulvovaginal Disease (ISSVD), officially proclaiming the name lichen sclerosus.[38]
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| リンク元 | 「硬化性苔癬」 |
| 拡張検索 | 「lichen sclerosus et atrophicus」 |