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SPECIAL REPORT ActaDV ActaDV Advances in dermatology and venereology Acta Dermato-Venereologica
Debunking the Myth of Wool Allergy : Reviewing the Evidence for Immune and Non-immune Cutaneous Reactions
Michaela ZALLMANN 1 , 2 , Pete K . SMITH 3 , Mimi L . K . TANG 2 , 4 , 5 , Lynda J . SPELMAN 6 , Jennifer L . CAHILL 7 , Gabriele WORTMANN 8 , Constance H . KATELARIS 9 , Katrina J . ALLEN 2 , 4 , 5 and John C . SU 1 , 2 , 4 , 5
1
Department of Dermatology , Monash University , Eastern Health , Box Hill , Victoria , 2 Murdoch Childrens Research Institute , Melbourne , Victoria ,
3
School of Medicine , Griffith University , Gold Coast and Bond University Medical School , Robina , Queensland , 4 Department of Paediatrics , The Royal Children ’ s Hospital , Melbourne , Victoria , 5 Department of Paediatrics , University of Melbourne , Melbourne , Victoria , 6 Queensland Institute of Dermatology and Veracity Clinical Research , Brisbane , Queensland , 7 The Skin and Cancer Foundation Inc ., Melbourne and Department of Dermatology , Alfred Health , Melbourne , Victoria , Australia , 8 The School of Materials , The University of Manchester , Manchester , United Kingdom , and 9 Department of Medicine , Campbelltown Hospital and School of Medicine , Western Sydney University , New South Wales , Australia
Although wool is commonly believed to cause irritant ( non-immune ) and hypersensitivity ( immune ) cutaneous reactions , the evidence basis for this belief and its validity for modern garments have not been critically examined . Publications from the last 100 years , using MEDLINE and Google Scholar , were analysed for evidence that wool causes cutaneous reactions , both immune-mediated ( atopic dermatitis exacerbation , contact urticaria , allergic contact dermatitis ) and non-immune-mediated ( irritant contact dermatitis , itch ). Secondary aims of this paper were to examine evidence that lanolin and textile-processing additives ( formaldehyde , chromium ) cause cutaneous reactions in the context of modern wool-processing techniques . Current evidence does not suggest that wool-fibre is a cutaneous allergen . Furthermore , contact allergy from lanolin , chromium and formaldehyde is highly unlikely with modern wool garments . Cutaneous irritation from wool relates to high fibre diameters ( ≥ 30 – 32 µ m ). Superfine and ultrafine Merino wool do not activate sufficient c-fibres to cause itch , are well tolerated and may benefit eczema management .
Key words : wool ; allergy ; atopic dermatitis ; contact dermatitis ; irritant dermatitis .
Accepted Mar 22 , 2017 ; Epub ahead of print Mar 28 , 2017 Acta Derm Venereol 2017 ; 97 : 906 – 915 .
Corr : Dr Michaela Zallmann , Department of Dermatology , Eastern Health , Faculty of Medicine , Monash University , Clayton Campus , 5 Arnold Street , Box Hill , Victoria , Australia 3128 . E-mail : m . zallmann @ gmail . com
Wool is frequently perceived by the general community as being prickly and itchy , two qualities that correlate with perceived textile intolerance ( 1 , 2 ). In a longitudinal global consumer survey ( 2012 – 2015 ) of 3,591 respondents , commissioned by Australian Wool Innovation ( AWI ), 43 % of consumers who declared they would not consider purchasing woollen garments believed wool to be too itchy , prickly or uncomfortable ( 3 ). Similarly , in the medical community , avoidance of wool garments in favour of cotton has been advocated for patients with atopic dermatitis ( AD ) dating back to before 1980 when wool intolerance was included as a minor criterion in the Hanifin & Rajka ( 4 ) diagnostic criteria for AD . However , the updated criteria for AD excludes wool intolerance as a diagnostic feature . It is now recognised that sensations of itch and prickle occur as a result of fibre properties , especially coarse fibre diameter (> 30 – 32 µ m ), common across many fibre types rather than properties specific to wool ( 5 – 7 ). Despite this , wools ’ reputation as a cutaneous irritant , in both medical and public arenas , remains common , and wool avoidance is frequently recommended by medical professionals , particularly to patients with AD .
In addition to concerns about irritancy , wool is frequently perceived as an allergen in the general community . The aforementioned AWI-commissioned survey showed that 9 % of consumers reported avoidance of wool garments because of self-identified wool allergy ( 3 ). Among the public , wool-evoked prickle and skin irritation are commonly attributed to allergy to wool , despite not being immunologically mediated ( 8 – 10 ). Heightened focus has been placed on allergy in both public and medical domains following evidence of exponential growth in IgE mediated allergic disease ( AD , asthma , allergic rhinitis and food allergy ) since the 1990 ’ s , particularly in western countries ( 11 ). The prevalence of AD amongst children under 17 years in the 2003 National Survey of Children ’ s Health ranged from 9.7 – 18.1 % across the USA ( 12 ). By comparison , in 2015 , 28.0 % of the Australian HealthNuts population-based cohort of 5,276 children , had a history of infantile AD , and 20.3 % had clinically documented signs of AD at 12 months ( 13 ). Although wool is commonly considered to be an allergen , there is a lack of high quality evidence to support this .
Several authors from the early 20 th century reported cases of dermatitis and urticaria allegedly resulting from wool sensitisation and allergy ( 9 , 14 – 21 ). These reports have been cited in subsequent papers as evidence of the allergenicity of wool . However , the findings from these publications should be interpreted with caution due to limitations and inconsistencies in methodology hitherto doi : 10.2340 / 00015555-2655 Acta Derm Venereol 2017 ; 97 : 906 – 915
This is an open access article under the CC BY-NC license . www . medicaljournals . se / acta Journal Compilation © 2017 Acta Dermato-Venereologica .