Dermatology: Practical and Conceptual


Image Letter | Dermatol Pract Concept. 2023;13(3):e2023196 1

A Case of Hair Cast After Isotretinoin Treatment
Ecem Bostan1, Aysel Cakir2,3

1 Cihanbeyli State Hospital, Dermatology and Venereology Clinic, Konya, Turkey

2 OsmaniyeYedi Mart Hospital, Dermatology and Venereology Clinic, Ankara, Turkey

3 Osmaniye Yeni Hayat Hospital, Dermatology and Venereology Clinic, Ankara, Turkey

Citation: Bostan E, Cakir A. A Case of Hair Cast After Isotretinoin Treatment. Dermatol Pract Concept. 2023;13(3):e2023196.  
DOI: https://doi.org/10.5826/dpc.1303a196

Accepted: February 24, 2023; Published: July 2023

Copyright: ©2023 Bostan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-
NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, 
distribution, and reproduction in any medium, provided the original authors and source are credited.

Funding: None.

Competing interests: None.

Authorship: All authors have contributed significantly to this publication.

Corresponding author: Ecem Bostan, Dermatology and Venereology Clinic, Cihanbeyli State Hospital, Atceken Avenue, Hastane Street, 
Cihanbeyli/Konya, 42850, Turkey. Telephone: +90 0332 673 40 93 E-mail: bostanecem@gmail.com

Case Presentation

A 20-year-old female patient was referred to the derma-

tology outpatient clinic due to the emergence of multiple, 

white, easily removable, irregularly shaped and distributed 

concretions along the hair shaft (Figure 1). No accompa-

nying inflammation or alopecia was detected. At the time 

of appointment, she was under oral isotretinoin treatment 

for acne vulgaris and the white concretions adherent to 

proximal hair shaft, had started to appear during the fourth 

month of the therapy. She was not using any other systemic 

or topical treatment. The differential diagnoses included 

peripilar keratin cast (PKC), white piedra, trichonodosis 

and pediculosis capitis. The patient did not report to have 

any other prior hair disease such as seborrheic dermatitis, 

psoriasis or folliculitis decalvans which may also be asso-

ciated with hair casts. Potassium hydroxide examination 

was negative, since the white granules were easily removed 

from the hair shaft by gentle pulling, pediculosis capitis was 

also ruled out. She was diagnosed with PKC associated with 

isotretinoin use, topical betamethasone and salicylic acid 

solution and ketoconazole 2% shampoo application re-

sulted in complete regression. Informed consent was taken 

from the patient for the publication of case details and clin-

ical pictures.

Teaching Point

PKC also known as hair cast, is characterized by tiny, white 

to yellowish, easily removable granules which encircle the 

hair shaft [1]. Hair casts are usually composed of hyperker-

atotic and parakeratotic cells derived from the outer root 

sheath [1]. The exact etiopathogenesis remains unclear but 

PKC may be seen in association with scalp disorders such as 

psoriasis, seborrheic dermatitis and tractional alopecia [1].  

Interestingly, Gutte [2] reported a case of scalp hair cast ob-

served after oral cyclosporine treatment. Herein, we would 

like to underline that isotretinoin may also be a cause of 

PKC. We suppose that sebum and hydration reduction in the 

hair shaft due to isotretinoin use, might have led to the for-

mation of PKC.



2 Image Letter | Dermatol Pract Concept. 2023;13(3):e2023196

References

1. França K, Villa RT, Silva IR, de Carvalho CA, Bedin V. Hair 

casts or pseudonits. Int J Trichology. 2011;3(2):121-122. 

DOI: 10.4103/0974-7753.90834. PMID: 22223977. PMCID: 

PMC3250010.

2. Gutte RM. Adult onset atopic dermatitis with secondary follic-

ular mucinosis with cyclosporine induced spiny fWollicular hy-

perkeratosis and hair casts. Indian J Dermatol. 2013;58(3):243. 

DOI: 10.4103/0019-5154.110863.PMID: 23723501. PMCID: 

PMC3667313.

Figure 1. (A) Multiple, scattered, white, easily removable, oval to cylindrical concretions along the hair shaft. (B) Dermoscopic image 

of the hair cast along the hair shaft.