Atopy and alopecia areata in North Indians

Introduction

Alopecia areata (AA) is a common disorder of hair loss the cause of which still remains unknown. Associations of AA with atopy, autoimmune diseases, Down′s syndrome and emotional factors have been studied by various investigators.[1],[2],[3],[4],[5],[6] Atopic disorders have been reported to occur with an incidence of 1 to 52% in patients with alopecia areata.[7],[8],[9],[10] It has also been observed that alopecia areata pursues a severe course in the presence of atopy and has an early onset of alopecia and a longer duration of disease with a poor response to treatment.[1],[2] However, the clinical experience has not been subjected to statistical evaluation. In a study from Chandigarh, no relationship was observed between presence of atopy and an early onset or an increased severity of alopecia areata.[8] Many previous studiest[1],[2],[8],[9],[10] have relied only on the history of atopy in the patient and/or family as an evidence of atopy and not intracutaneous test. We evaluated the effect of associated atopy on severity and age at onset of alopecia areata by applying statistical methods.

Materials and Methods

One hundred consecutive patients above the age of 12 years with alopecia areata were studied during the year 1997. A comprehensive medical history was obtained from each patient with a special reference to personal and family history (parents and sibs only) of atopic disorders which included bronchial asthma, nasal allergy and atopic dermatitis as recommeded by the expert groups.[12],[13],[14] Alopecia areata was classified into circumscribed, extensive and totalis/universalis type. Less than 10 patches of hair loss was labelled as circumscribed areata while extensive alopecia areata was defined as hair loss involving more than 40% scalp and/or more than 10 patches on the scalp, arms, legs or other sites. Alopecia areata, totalis/universalis and extensive alopecia areata were considered as severe alopecia areata.

Fifty patients selected on the basis of the random table were subjected to intracutaneous skin sensitivity tests after informed consents.[11] Intracutaneous test was carried out with eight common allergens (1:500 dilution) female cockroach, Alternaria teni\us, fumigatus, Ageratum conyzoides, Cassia siamea, Prosopis juliflora, Cynodon daction wheat grain dust (supplied by Council of Scientific and Industrial Research, Delhi). These allergens were selected based on experience in Allergy Clinic at Avanced Paediatrics Centre, PGIMER, Chandigarh. In all the patients a positive control with 0.01% histamine base solution and a negative control test with buffered normal saline were performed. The size of wheal and flare was recorded after 15-20 minutes as the mean of the largest diameter and its orthogonal diameter. A skin reaction which was 5mm more than the reaction observed with the saline control solution was taken as a positive test.

Thirty age and sex matched controls with no personal or family history of atopy were also subjected to intracutaneous tests.

Atopy was classified into 4 types as i) First degree relatives with atopy ii) patient with atopy, iii) patient and first degree relatives with atopy, iv) positive intracutaneous tests. A correlation of above types of atopy was examined with age at onset of alopecia areata and severe alopecia and duration of disease.

The statistical analysis was carried out using the Chi square test.

Results

Patients with alopecia areata included 76 males and 24 females. Majority of them (76%) were between 20 to 40 years and 92% had an onset of alopecia areata before the age of 40 years. Mean duration of disease was 7.1 months (range 1 day to 19 years). Circumscribed alopecia areata was observed in 76% patients and severe alopecia areata in 24%, which included 21 patients with extensive alopecia and 3 with alopecia universalis.

Historical evidence of atopy was present in 50 patients and/or first degree relatives (parents and sibs only).

Evidence of atopy was present in patients alone in 23, patients and first degree relatives in 11 and first degree relatives alone in 16 patients Allergic rhinitis was the most common and was observed in 42 patients or first degree relatives followed by bronchial asthma in 6 and atopic dermatitit in 2.

Intracutaneous tests were positive to one or more allergens in 23 (46%) out of 50 patients with alopecia areata compared to 7(23.3%) out of 30 control (no personal or family history of atopy;p< 0.05). The correlation between presence of atopy by history or intracutaneous tests and severe alopecia, age at onset and duration of alopecia is depicted in [Table - 1] and [Table - 2].

There was trend towards increasing frequency of severe alopecia and presence of atopy in both patient and first degree relatives and positive intracutaneous tests, but the results did not attain statistical significance [Table - 1] and [Table - 2]; P>0.05). Similarly no correlation was found in age at onset and duration of alopecia and presence of atopy [Table - 1].

Discussion

Alopy has been reported to occur with an increased frequency in patients with alopecia areata.[1],[2],[8],[9],[10] [Table - 1]. The atopic type in Ikeda′s classification comprised 10% of 1989 patients′ similarly 11% of 736 patients studied by Muller and Winkelmann[2] had concomitant asthma or atopic dermatitis. In the present study atopy was detected in increased frequency in patients with alopecia areata. Based on a detailed history 50% of our patients had evidence of atopy (patient alone in 23, patients and first degree relatives in 11 and first degree relatives alone in 16). These results are similar to those reported by Penders[12] and Young et al.[13] Atopy is reported in 10% to 52.4% [Table - 3] of patients with alopecia areata and findings are within this range. Alopecia areata may become severe in upto 75% patients who have associated atopy.[1],[2],[3] In present study despite increasing frequency of severe alopecia in atopics the results did not attain statistical increasing significance [Table - 1] and [Table - 2]. It is in agreement with our previous report. Muller Winkelmann Ikeda[1],[2] had stated that patients with atopy have onset at relatively younger age and have longer duration of disease but same was not confirmed in the present study.

It is concluded that associated atopy apparently does not affect the severity of alopecia areata in north Indians. Previous studies[1],[2] created converse impression without statistical analysis of their data. It is possible that severity of associated atopic disorders may be a critical factor in determining the severity of alopecia areata than the mere presence of atopic disorder. It has been reported that atopic dermatitis is less severe in Asians and in other underdeveloped and tropical countries.[17],[18] It may partly explain our findings and additional variation may be due to genetic factors.