DEFINITION
The disease definition according to a specific consensus conference or to The Diseases Database based on the Unified Medical Language System (NLM)
Also the link to the corresponding Mesh term has to be created
EPIDEMIOLOGY
age, sex, seasonality, etc
SYMPTOMS
DIAGNOSIS
histopathology
radiology
NMR
laboratory tests
PATHOGENESIS
PATIENT RISK FACTORS
Vascular
Genetic
Acquired
Hormonal
Genetic
Different levels of 5alpha-reductase type I and II, aromatase, and androgen receptor in hair follicles of women and men with androgenetic alopecia. 1997
J Invest Dermatol. 1997 Sep;109(3):296-300.
Sawaya ME, Price VH.
Department of Medicine, University of Florida, Gainesville 32610, U.S.A.
In this study, 12 women and 12 men, ages 18-33 y, with androgenetic alopecia were selected for biopsies from frontal and occipital scalp sites. The androgen receptor, type I and II 5alpha-reductase, cytochrome P-450-aromatase enzyme were measured and analyzed in hair follicles from these scalp biopsies. Findings revealed that both women and men have higher levels of receptors and 5alpha-reductase type I and II in frontal hair follices than in occipital follicles, whereas higher levels of aromatase were found in their occipital follicles. There are marked quantitative differences in levels of androgen receptors and the three enzymes, which we find to be primarily in the outer root sheath of the hair follicles in the two genders. Androgen receptor content in female frontal hair follicles was approximately 40% lower than in male frontal hair follicle. Cytochrome P-450-aromatase content in women's frontal hair follicles was six times greater than in frontal hair follicles in men. Frontal hair follicles in women had 3 and 3.5 times less 5alpha-reductase type I and II, respectively, than frontal hair follicles in men. These differences in levels of androgen receptor and steroid-converting enzymes may account for the different clinical presentations of androgenetic alopecia in women and men.
Acquired
Skin disorders and thyroid diseases.
TISSUE SPECIFIC RISK FACTORS
anatomical (due its structure)
vascular (due to the local circulation)
physiopathological (due to tissue function and activity)
Cadherin 23 is a component of the tip link in hair-cell stereocilia
RXR-alpha ablation in skin keratinocytes results in alopecia and epidermal alterations. 2001
Interactions of the vitamin D receptor with the corepressor hairless: analysis of hairless mutants in atrichia with papular lesions. 2007
COMPLICATIONS
THERAPY
Cadherin 23 is a component of the tip link in hair-cell stereocilia
RXR-alpha ablation in skin keratinocytes results in alopecia and epidermal alterations. 2001
Interactions of the vitamin D receptor with the corepressor hairless: analysis of hairless mutants in atrichia with papular lesions. 2007
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Comorbidity profiles among patients with alopecia areata: The importance of onset age, a nationwide population-based study. 2011
Department of Dermatology, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Dermatology, National Yang-Ming University, Taipei, Taiwan.
Abstract
BACKGROUND:
Alopecia areata (AA) is considered an autoimmune disease with undetermined pathogenesis. Age at onset predicts distinct outcomes. A nationwide study of the relationship of AA with associated diseases stratified by onset age has rarely been reported.
OBJECTIVE:
We sought to clarify the role of atopic and autoimmune diseases in AA, thereby better understanding its pathogenesis.
METHODS:
A total of 4334 patients with AA were identified from the National Health Insurance Database in Taiwan from 1996 to 2008. A national representative cohort of 784,158 persons served as control subjects.
RESULTS:
Among patients with AA, there were significant associations with vitiligo, lupus erythematosus, psoriasis, atopic dermatitis, autoimmune thyroid disease, and allergic rhinitis. Different ages at onset resulted in disparate comorbidities. Increased risk of atopic dermatitis (odds ratio [OR] 3.82, 95% confidence interval 2.67-5.45) and lupus erythematosus (OR 9.76, 95% confidence interval 3.05-31.21) were found in childhood AA younger than 10 years. Additional diseases including psoriasis (OR 2.43) and rheumatoid arthritis (OR 2.57) appeared at onset age 11 to 20 years. Most atopic and autoimmune diseases were observed at onset ages of 21 to 60 years. With onset age older than 60 years, thyroid disease (OR 2.52) was highly related to AA. Moreover, patients with AA had higher risk for more coexisting diseases than control subjects.
LIMITATIONS:
We could not differentiate hypothyroidism from hyperthyroidism.
CONCLUSIONS:
AA is related to various atopic and autoimmune diseases. Different associated diseases in each onset age group of AA can allow clinician to efficiently investigate specific comorbidities.