Objective: Report a rarely documented side effect of dopaminergic therapy and review the literature on this aspect, highlighting the underlying mechanisms hypothetically involved.

Background: Levodopa (LD) has been used to treat Parkinson’s disease since 1961 and its adverse effects as well as its long-term toxicity has been investigated over the decades. However, some of its effects and the ways that lead to its production have been less studied given its lower frequency, as is the case of alopecia, that we describe in this patient.

Method: We describe the case of a seventy-nine Parkinson’s disease patient with no relevant personal history except hypertension and diabetes, which presents a rapidly progressive hair loss after starting treatment with levodopa/carbidopa gradually increased to a dose of 300 mg of levodopa per day. We include an image of the patient before the start of LD [Figure 1], and other images after treatment [Figure 2][Figure 3][Figure 4][Figure 5].

Results: Other possible causes of alopecia were investigated, such as hypothyroidism, protein and vitamin deficiency and toxicity to other drugs without finding causality. The patient has not family or personal history of alopecia areata, pernicious anemia, vitiligo, Hashimoto thyreoditis, or Addison’s disease. After the withdrawal of levodopa the patient partially recovered the hair although the graying persisted. Treatment with rasagiline was continued in monotherapy with slight worsening of motor function and without new adverse effects.

Conclusion: Whereas digestive symptoms and motor complications secondary to levodopa therapy, such as dyskinesias and wearing off, are well known, only a few cases of alopecia have been described in relation to dopaminergic therapy, more frequently in women and with dopamine receptor agonists. The precise mechanism by which dopamine induces hair loss remains to be elucidated, however, there are some preliminary studies that has demonstrated that dopamine could act as an inhibitor of hair growth, by the promotion of catagen induction and that dopamine 1 receptor transcripts are present in human hair follicles. Further studies are necessary for a better characterization of this relationship.

References: [1] Hideto M, Tomoyoshi K. Hair loss induced by dopamine agonist: case report and review of the literature. Parkinsonism and Related Disorders 2003; 10: 51–52. [2] Langan EA, Lisztes E, Bíró T, Funk W, Kloepper J.E, Griffiths C.E.M, Paus R. Dopamine is a novel, direct inducer of catagen in human scalp hair follicles in vitro. British Journal of Dermatology 2012; 168: 520–525. [3] Marshall A, Williams MJ. Alopecia and levodopa. Br Med J 1971; 2: 47. [4] Tabamo RE, Di Rocco A. Alopecia induced by dopamine agonists. Neurology 2002; 58: 829–830.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/sudden-alopecia-secondary-to-levodopa-treatment/