alopecia areata ( aa ) is a chronic , organ specific autoimmune disease , probably mediated by autoreactive t cells , which affects the hair follicles and sometimes the nails .
there is a high frequency of a family history of aa in affected persons , ranging from 10% up to 42% of cases .
clinically , the disease manifests as patchy alopecia , reticulate alopecia , ophiasis , ophiasis inversus ( sisaphio ) , alopecia totalis or alopecia universalis . a new subtype of aa is acute diffuse and total alopecia of the female scalp characterized by rapid progression of diffuse alopecia of the female scalp , marked female predominance and a favorable prognosis .
nail changes ( diffuse fine pitting , longitudinal ridging , thin and brittle fingernails and toenails and trachyonychia ) may be seen in 3 - 30% of patients .
dermatoscopy is a noninvasive technique allowing rapid and magnified in vivo observation of the skin with the visualization of morphologic features often imperceptible to the naked eye .
dermatoscopy may be useful for differential diagnosis of difficult cases , in particular in diffuse aa or in patients with total hair loss by the presence of cadaverized hairs ( black dots [ bds ] ) , exclamation mark hairs ( tapering hairs [ th ] ) , broken hairs ( bhs ) , yellow dots ( yds ) and clustered short vellus hairs ( svhs ) in the hair loss areas .
this study was carried out in 75 patients of aa visiting dermatology outpatient department of a tertiary care center in north karnataka between november 2012 and july 2013 .
the clinical diagnosis of aa was established after a detailed history taking including past and family history and clinical examination .
grading of aa was done using the following scale : scalp hair loss : s0 , no hair loss ; s1 , < 25% hair loss ; s2 , 26 - 50% hair loss ; s3 , 51 - 75% hair loss ; s4 , 76 - 99% hair loss ; s5 , 100% hair loss . body hair loss : b0 , no body hair loss ; b1 , some body hair loss ; b2 , 100% body ( excluding scalp ) hair loss .
a digital dermatoscope ( of magnification 25 and 60 ) was used for the evaluation .
the mean age of the patients at presentation was 26.94 years , youngest being 10 months and oldest being 68 years .
alopecia areata patients categorized based on age the mean age of onset was 23.58 years .
the mean duration of the current episode in recurrent cases was 5.7 months ( 1 week-3 years ) .
a total of 46 patients had their first episode of aa at presentation ( males 32 , females 14 ) .
patchy alopecia was the most common pattern of aa seen in 55 ( 73.3% ) patients ( 43 males , 12 females ) .
29 patients ( 23 males , 6 females ) had a single patch and 26 patients ( 20 males , 6 females ) had multiple patches .
the other patterns observed were : ophiasis - 9 cases ( 6 males , 3 females ) , sisaphio - 3 cases ( 1 male , 2 females ) , reticulate - 2 cases ( 1 male , 1 female ) , diffuse - 3 cases ( 1 male , 2 females ) , alopecia totalis in 1 female and alopecia universalis in 2 males [ table 1 ] .
55 patients showed involvement of the scalp ( 34 males - 62.96% , 21 females - 100% ) which included : occiput - 27 , frontal and vertex - 19 each , temporal - 7 and parietal - 5 .
the other sites involved were - beard 13 ( 13 males - 24.07% ) , moustache 8 ( 8 males - 14.81% ) , eyebrows 8 ( 4 males - 7.4% , 4 females - 19.04% ) , eyelashes 2 ( 1 male - 1.85% , 1 female - 4.76% ) , limbs 2 ( 2 males - 3.7% ) and alopecia universalis 2 ( 2 males - 3.7% ) [ graph 2 ]
. sites of involvement in alopecia areata in both sexes a single site was involved in 59 patients ( scalp only - 46 , beard only - 9 , moustache only - 3 , eyebrows only - 1 ) .
11 patients had involvement of 2 sites and > 2 sites were involved in 5 patients .
these included pitting in 7 patients , ridging in 1 patient and striate leuconychia in 3 patients .
the dermatoscopic features seen in our patients were as follows : yds-43 ( 57.33% ) , bds - 63 ( 84% ) , bh - 28 ( 37.33% ) , svh - 51 ( 68% ) and th - 14 ( 18.67% ) [ figures 1 - 5 ] .
all these dermatoscopic features were seen in 7 patients whereas 2 patients had none of the above features .
dermoscopic features in various patterns of aa 44 patients ( 58.67% ) had received some form of treatment at presentation , whereas 31 patients ( 41.33% ) had not taken any treatment .
75% of treated patients showed presence of svh at presentation in contrast to 51.6% of untreated patients .
the various dermoscopic features in patients with and without treatment is tabulated in table 4 .
the onset is within the first three decades of life although it can start at any age .
the sex incidence is probably equal . in our study , males were most commonly affected than females with a male : female ratio of 2.57:1 .
, whereas the study conducted by inui et al . , showed an increased female preponderance .
the mean age of onset of aa was 23.58 years which was consistent with the previous studies .
patchy alopecia , being the most common pattern of aa in our study , was seen in 73.3% of patients .
mane et al . , also noted patchy alopecia as the most common pattern involving 46.7% and 87.7% of patients respectively .
dermoscopy has been established as an indispensable tool in the diagnosis and follow - up of hair disorders . in aa ,
dermoscopy of active disease shows yds , dystrophic hairs , as well as cadaverized ( bds ) and exclamation mark hairs .
yds are a powerful new tool in the diagnosis of hair loss diseases initially proposed by ross et al .
yds are marked by a distinctive array of yellow to yellow - pink , round or polycyclic dots that vary in size and are uniform in color .
they represent distention of the affected follicular infundibulum with keratinous material and sebum . in aa , degenerating follicular keratinocytes probably constitute the bulk of the yd . in a study conducted by inui et al .
, yds were seen in 63.7% ( 191/300 ) of cases in contrast to ross et al .
the low incidence in our study may be attributed to the skin color of our patients which might make the yds difficult to perceive .
ths ( exclamation marks hairs ) are characterized by wider diameter in the distal shaft and thinner diameter in the proximal shaft .
this pattern marks presence of the lymphocytic inflammatory infiltrate affecting the hair bulb and thus , producing thinner hair shaft .
ths were seen in 31.7% ( 95/300 ) cases of aa by inui et al . and
we noted ths in 14 ( 18.67% ) cases which was consistent with the previous studies .
bhs , considered to be dystrophic hairs produced by the least severely affected follicles in aa , are clinical markers of the disease activity and severity .
inui et al . , demonstrated bhs in 45.7% ( 137/300 ) of alopecia cases .
bds ( formerly  cadaverized hairs  ) which represent pigmented hairs broken or destroyed at scalp level are characteristic of black haired individuals .
this sign is not seen in white population due to the hair color and cuticle resistance .
these are a sensitive marker not only for disease activity , but also for the severity of aa . in our study ,
inui et al . , demonstrated bds in 44.3% ( 133/300 ) cases of aa .
the presence of svhs indicates the nondestructive nature of aa , allowing hair regrowth whether or not it results in completely mature hair shafts the pigmented hairs of asians facilitate the detection of svhs by dermoscopy .
the regrowth of svhs can be seen after treatment in dermoscopy even when the recovered hairs are hardly perceived by the naked eye .
short hypopigmented vellus hairs are characteristic of remitting disease . in our study , 51 out of 75 patients ( 68% ) demonstrated the presence of svhs .
our findings were consistent with the previous studies conducted by inui et al . , where svhs were observed in 72.7% ( 218/300 ) of cases .
the higher incidence of svh in our study was probably due to the various forms of treatment already received by 58.67% of patients before their first visit to our center .
demonstrated that for diagnosis of aa , yds and svhs were the most sensitive markers .
the most common dermoscopic finding observed was bds , followed by svhs , yds , bhs and ths .
 background : dermatoscopy is a new noninvasive tool for the diagnosis of various skin and hair disorders . 
 dermatoscopy of alopecia areata ( aa ) shows various specific features , which may aid in confirming the diagnosis.aims:the aim of this study was to determine the various clinical patterns and the dermatoscopic features of aa.materials and methods : a total of 75 patients of aa were evaluated with a dermatoscope ( magnification 25 and 60).results : the mean age of onset of aa was 23.58 years . 
 males were more commonly affected . 
 scalp was most commonly involved . 
 patchy alopecia was the most common pattern observed . 
 10 patients showed concomitant nail changes . 
 the dermatoscopic features included yellow dots ( yds ) in 43 ( 57.33% ) patients , black dots ( bds ) in 63 ( 84% ) cases , broken hairs ( bhs ) in 28 ( 37.33% ) cases , short vellus hair ( svh ) in 51 ( 68% ) patients and tapering hair ( th ) in 14 ( 18.67% ) cases.conclusion:the most common dermatoscopic finding observed was bds , followed by svhs , yds , bh and th . 