Transient Alopecia after Embolization of Intracranial Aneurysm: Case Report and Review

Endovascular interventional procedures are widely used for intracranial arterial pathologies treatment. They also require realization of fluoroscopy, a technique that relies on the properties of X-rays to obtain real-time images.[1] Many cases of transient alopecia after this procedure have been reported.

A previously healthy, 45-year-old male was admitted with an intracranial hemorrhage after a spontaneous rupture of an aneurysm in the anterior communicating artery. Two embolization procedures were required. Two weeks after the last one, he experienced a partial hair loss, comprising the left temporoparietal scalp region. A 7.5 cm-sized alopecia plaque was observed, which presented with striking angular edges with rectangular morphology [Figure 1a]. Pull test was positive. Trichoscopy showed black dots, as well as short vellus hairs [Figure 1b]. Lack of peladic hairs ruled out alopecia areata. Skin biopsy revealed multiple pilosebaceous units with minimal perifollicular lymphocitic infiltrate, as well as obliterated follicles without signs of fibrosis or lichenoid reaction. After 2 months, the patient showed complete hair regrowth and no treatment was prescribed.

Figure 1.

(a) Alopecia areata in the patient's left temporoparietal region. Note the angular edges which give it a perfectly square contour. (b) Trichoscopy performed on the edge of the alopecia area. Black dots can be observed, as well as short vellus hair

Transient radiation alopecia (TRA) is an adverse effect, which usually appears with accumulated doses between 3 and 6 Gy. Greater doses than 6 Gy may cause scarring alopecia.[1,2,3,4,5,6,7,8,9,10] This is caused by the simultaneous entry of multiple follicular cells in catagen phase. The usual dose of radiation produced by a fluoroscopy X-ray unit is usually between 0.02 and 0.05 Gy/min, which increases with the sequential use of other procedures that use radiation.[1]

Fifty-eight cases of TRA have been reported after intracranial arterial embolization, being more frequent in women, with a ratio of 1.41:1 [Table 1]. The age varies from 13 to 70 years (mean age: 42.87), but most of the patients described were between 30 and 50 years. Patients report sudden hair loss in a short period of time, producing plaques of alopecia whose size and shape vary depending on the model of the device used. These areas show characteristic angular edges, which along with the medical history is essential for the differential diagnosis with alopecia areata.[1,2,3,4,5,6,7,8,9,10]

Table 1.

Characteristics of patients with transient radiation alopecia reported in the literature since 1994

Author	Age	Gender	Radiation (Gy)	Biopsy	Latency (weeks)	Resolution (months)	Treatment
S. Podlipnik	38	Male	ED: >4	No	4	2	No
W. Huda	34	Female	6.6	No	NS	3	NS
G.M. Garnacho	39	Male	ED: 3	No	2	5	No
A. César	26	Female	5	Yes	1	3	No
Freysz et al.[1] (18 patients)	AR: 19-58	6 male, 12 female	2.5-12.3	No	2-4	2-3	No
D’incan et al.[2] (6 patients)	AR: 27-47	4 male, 2 female	NS	No	2	3-4	No
M. Krasovec	32	Male	NS	No	2	3	No
N. Marti	29	Female	ED >3	No	2	4	No
W.S. Lee (5 patients)	AR: 40-57	1 male, 4 female	ED >2	Yes	2	5-6	Cryotherapy and dexamethasone
V. López	44	Female	ED >3	No	3	4	No
Wen et al.[3]	33	Male	ED >3	No	2	2	NS
Nannapaneni et al.[4] (2 patients)	AR: 31-45	2 female	3.83-4.07	No	4	6	NS
Seol et al.[10] (3 patients)	AR: 33-51	2 male, 1 female	NE	Yes	2	3-4	Minoxidil and topical corticosteroids and triamcinolone
Verma et al.[5]	47	Female	ED >3	No	2	3	No
Vaccaro et al.[6]	NS	Female	3.92	No	4	2	No
Vazquez et al.[7]	13	Male	NS	No	6	6	No
Cho et al.[8] (10 patients)	AR: 35-70	2 male, 8 female	NS	Yes	1-8	3-4	No
Lee et al.[9] (2 patients)	AR: 49-55	2 male	4.2-5.7	No	2	4-5	Topical minoxidil
C. Bernárdez	32	Female	NS	Yes	4	2	No

AR – Age range; ED – Estimated dose; NS – Not specified

The cumulative radiation dose was in most cases greater than 3 Gy, with 92% of cases ranging between 3 and 6 Gy. Only one patient developed alopecia with doses below 3 Gy,[1] and four cases received doses above 6 Gy.[1] Only one case of scarring TRA has been reported.[8] In the case of our patient, we do not know the exact dose of radiation received, but a total dose greater than 3 Gy was estimated due to the need of a second embolization.

In trichoscopy, the most common findings include black dots and yellow dots, followed by short, vellus hairs. Broken hairs and white dots are less common.[8,10] These findings can be observed in alopecia areata. However, exclamation hairs are often seen in the latter, a finding that is not present in TRA.

Histological findings were described in 11 patients,[8,9,10] and they included anagen or catagen follicles lacking inflammatory infiltrate or scar tissue. Differential diagnosis should be made mainly with alopecia areata, in which a characteristic peri/intrabulbar lymphocytic inflammatory infiltrate with a “honey-comb” image is usually observed.

Time from the embolization procedure to the onset of alopecia ranges from 1 to 8 weeks, occurring in 93% of cases between the 2^nd and the 4^th week. The symptoms resolve spontaneously between 2 and 6 months, with complete regrowth with terminal hairs without color or thickness alterations, except in one case where the hair presented a more grayish hue, and in another described case, the patient presented scarring alopecia without repopulation.[8] In some cases, superficial cryotherapy, topical corticosteroids, topical minoxidil, and/or intralesional triamcinolone were applied, without significant differences in terms of evolution compared to the rest of untreated patients.[9,10]

In conclusion, TRA is generally a transient condition that resolves without the need of treatment. Given the increase of such interventional procedures in recent years, it is important to know this entity and differentiate it mainly from alopecia areata. It should also be considered adding this side effect to the informed consent of such interventions. For a correct diagnosis, it is essential to carry out an adequate clinical history oriented to interventional procedures undergone by the patient and should be suspected when facing an area of alopecia with sharp and angular edges.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.