Typically, alopecia areata (AA) presents with sharply demarcated round foci. Trichoscopy can provide valuable information; scalp biopsy is indicated only in exceptional cases. The course of AA varies greatly from individual to individual. One-third of patients experience spontaneous remission within six months of initial manifestation. An unfavorable prognostic marker is nail involvement.
Alopecia areata (AA) can occur at any age, with initial manifestation occurring in 40% of patients before the age of 20 years and in 83-88% by the age of 40 years, according to epidemiological data [1]. According to the current state of knowledge, it is assumed that the etiopathogenesis can be explained by an autoimmunologically induced dysregulation of the hair follicles in interaction with genetic and external factors [2,3]. A genetic disorder appears to disrupt the hair root camouflage at a certain stage in the hair growth cycle, allowing dysregulated immune cells to attack the hair root [4]. “There is an association with other autoimmune diseases, especially thyroid autoimmune diseases such as Graves’ disease and Hashimoto’s thyroiditis,” explained Stephanie Marie Huber, MD, Dermatology, University Hospital Basel [5].
Circular hair loss in varying degrees
“Clinically, the spectrum of alopecia areata is very broad, ranging from localized, circumscribed hair loss in the area of the scalp, in the area of the beard, on the eyelashes and eyebrows, to a complete loss of scalp hair, to the maximum variant with a complete loss of the entire body hair,” said Dr. Huber [5]. If the entire capillitium is affected, this is called alopecia areata totalis; if the body is completely hairless, it is called alopecia areata universalis. Alopecia with ophiasis pattern (band-like hair loss temporally or occipitally) also belongs to the more severe forms.
Trichoscopy and hair plucking test: obligatory non-invasive examinations
In addition to a detailed medical history, a careful examination of the scalp, face and entire body, must be performed. “Classically, sharply demarcated and oval alopecic foci are found, sometimes with isolated residual hair in the sense of telogen hair or depigmented hair” [5]. Clinical inspection should always be supplemented by trichoscopy and a hair pluck test. In AA, foci classically spread centrifugally, so the hair pluck test is positive at the active edge of the foci. Trichoscopy is important for distinguishing between non-scarring and scarring hair diseases, on the one hand, and for evaluating disease activity, on the other [2]. The most common dermoscopic findings in AA are “yellow dots,” “black dots,” broken hairs, exclamation point hairs, and vellus hairs. Less commonly described findings include upright hairs, tapered hairs, and Pohl-Pinkus constrictions [2]. The “yellow dots” occur mainly in long-standing lesions and in more severe forms of AA. Although they are a typical finding of AA, they can also occur in other hair disorders such as androgenetic alopecia or trichotillomania [3]. Exclamation mark hairs are pathognomonic for AA and typically found at the active margin of AA foci [3].
It is essential that patients are also examined for nail changes, as this may provide important prognostic information (Box).
Histopathology makes inflammatory filtrate visible
A scalp biopsy is indicated only in exceptional cases, for example when one suspects scarring alopecia, the speaker explained. She recommends cutting 2×4 mm punch biopsies 1× vertically and 1× horizontally. Histopathologically, AA foci are characterized by a “swarm-like” lymphocytic inflammatory infiltrate around the bulb of hair follicles, leading to disruption of regular growth activity and dystrophy [5,6]. If the clinical and histopathological findings do not allow a definite diagnosis, a fungal culture or serology to exclude other autoimmune diseases or infectious diseases (for example, syphilis) may be useful as additional diagnostic measures [2].
Congress: Swiss Derma Day
Literature:
- Villasante Fricke AC, Miteva M: Epidemiology and burden of alopecia areata: a systematic review. Clin Cosmet Investig Dermatol 2015; 8: 397-403.
- Lintzeri DA, et al: Alopecia areata – Current understanding and management. J Dtsch Dermatol Ges 2022; 20(1): 59-93.
- Dumke A-K, Rhein D, Elsner P: Treatment of alopecia areata with diphenylcyclopropenol: casuistry and current literature review. Act Dermatol 2012; 38: 326-330.
- “Procedure for Alopecia – What Happens in the Hair Consultation?”, https://kreisrunderhaarausfall.de/wp-content/uploads/koepfchen_36.pdf,(last accessed Jan. 13, 2023).
- “Alopecia areata – new evidence,” Stephanie Marie Huber, MD, Swiss Derma Day and STI reviews and updates, Jan. 12, 2023.
- Paus R, Bulfone-Paus S, Bertolini M: Hair follicle immune privilege revisited: the key to alopecia areata management. J Investig Dermatol Symp Proc 2018; 19: S12-17.
DERMATOLOGIE PRAXIS 2023; 33(1): 29 (published 2/16/2013, ahead of print).
