Diagnosis
Alopecia areata has an unpredictable course. Some patients experience spontaneous regrowth, as well as relapse, which can complicate the assessment of hair loss.1
Additional confounding factors of other hair loss disorders can present in a patient, along with variation in hair density and thickness between individuals.1
Severity of Alopecia Tool (SALT) can be helpful in assessing scalp hair loss.2
There are two different ways the SALT score can be used and presented3:
Reprinted with permission from the Journal of the American Academy of Dermatology.4
The scalp is divided into 4 regions with a pre-assigned percentage of surface area. The percentage of hair loss within one area is multiplied by the percentage of surface area that region represents to give an adjusted percentage (e.g., 20% hair loss on the right scalp: 20% x 0.18 = 3.6%). Then, the adjusted percentages for each region are added together to get the total percentage of hair loss, expressed as a SALT score.2
Assessment of Severity
Alopecia Areata—Investigator’s Global Assessment (AA-IGA)
While the SALT score can be used to assess the extent of scalp hair loss, the AA-IGA is an ordinal outcome measure that categorizes the severity of scalp hair loss based on SALT score2,5:
0 = None (SALT 0%)1 = Limited (SALT 1% to 20%)
2 = Moderate (SALT 21% to 49%)
3 = Severe (SALT 50% to 94%)
4 = Very Severe (SALT 95% to 100%)
See Related Resources below for an overview of the Alopecia Areata Scale (AASc), a multidimensional assessment tool for evaluating the severity of AA.
Nail Involvement
Nail changes may also be present with alopecia areata. Nail abnormalities like pitting, crumbling, trachyonychia, and red spots on the lunula are more common among patients with severe alopecia areata (50.5% in severe disease vs. 13% with milder disease).3,6
Image (© 2007 Waikato District Health Board) used with permission from: https://www.dermnetnz.org/.7
There are different ways to categorize hair loss. Other physician-assessed alopecia areata measurements take into account density (Alopecia Density and Extent—ALODEX)1 and progression (Alopecia Areata Progression Index—AAPI).8
Related Resources
Alopecia Areata in Black Patients: Clinical Pearls Presented by Dr. Victoria Barbosa
Dr. Victoria Barbosa provides clinical insights to educate dermatologists about special considerations in the diagnosis and management of alopecia areata in black patients.
Assessing Alopecia Areata Patient Severity With Dr. Senna and Dr. King
Dr. Maryanne Senna provides an overview of current gaps in alopecia areata disease severity classification, and Dr. Brett King introduces the Alopecia Areata Scale (AASc) as a new multidimensional scale for clinical use.
Alopecia Areata Scale (AASc) Overview
Resource for dermatologists that provides an overview of the Alopecia Areata Scale (AASc), a multidimensional assessment tool designed to more effectively and consistently evaluate the severity of AA in clinical practice.
Understanding SALT Scores in Your Patients With Alopecia Areata: A Visual Guide to the Severity of Alopecia Tool (SALT)
Resource for dermatologists that provides photo representations of Severity of Alopecia Tool (SALT) scores in patients with severe alopecia areata.
References
- Standardizing outcome measures in alopecia areata. National Alopecia Areata Foundation. Accessed May 29, 2020. https://www.slideshare.net/NationalAlopeciaAreataFoundation/standardizing-outcome-measures-in-alopecia-areata
- Olsen EA, Hordinsky MK, Price VH, et al. National Alopecia Areata Foundation. Alopecia areata investigational assessment guidelines—Part II. National Alopecia Areata Foundation. J Am Acad Dermatol. 2004 Sep;51(3):440-447. doi:10.1016/j.jaad.2003.09.032
- Pratt CH, King LE Jr, Messenger AG, et al. Alopecia areata. Nat Rev Dis Primers. 2017;3:17011. doi:10.1038/nrdp.2017.11
- Olsen EA, Canfield D. SALT II: a new take on the Severity of Alopecia Tool (SALT) for determining percentage scalp hair loss. J Am Acad Dermatol. 2016;75(6):1268-1270. doi:10.1016/j.jaad.2016.08.042
- Wyrwich KW, Kitchen H, Knight S, et al. The alopecia areata investigator global assessment scale: a measure for evaluating clinically meaningful success in clinical trials. Br J Dermatol. 2020;183(4):702-709. doi:10.1111/bjd.18883
- Roest YBM, van Middendorp HT, Evers AWM, et al. Nail involvement in alopecia areata: A questionnaire-based survey on clinical signs, impact on quality of life and review of the literature. Acta Derm Venereol. 2018;98(2):212-217. doi:10.2340/00015555-2810
- Alopecia-nails. alopecia-areata-nails.jpg. Image (© DermNet New Zealand) used with permission from: https://www.dermnetnz.org/permission/image/27972 (Accessed November 2018). Image is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 New Zealand (CC BY-NC-ND 3.0 NZ) License: https://creativecommons.org/licenses/by-nc-nd/3.0/nz/legalcode
- Jang YH, Moon SY, Lee WJ, et al. Alopecia areata progression index, a scoring system for evaluating overall hair loss activity in alopecia areata patients with pigmented hair: A development and reliability assessment. Dermatology. 2016;232(2):143-149. doi:10.1159/000442816
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