Prolactina y Psoriasis

Dr. Warren Heymann on Prolactin and Its Role in Stress-Induced Psoriasis: Milking the Data

Patients will readily acknowledge that stress worsens their psoriasis. When asked how this happens, I respond by mentioning the "mind–body connection" and using the term psychoneuroimmunology. Patients nod in agreement, feigning understanding; appropriately so, because, frankly, I don't understand it either.

The latest data suggest that the bon mot should be "psychoneuroendocrine immunology" because of the increasing evidence that hormones (corticosteroids, epinephrine, thyroid hormone, insulin, and leptin) may influence psoriasis. The potential role of prolactin in stress-aggravated psoriasis has been the focus of recent attention.¹

The initial notion that prolactin could worsen psoriasis was considered more than 30 years ago, with the observation that bromocriptine (a dopaminergic agonist that inhibits prolactin secretion) improved or remitted in 80% of 60 patients with all variants of psoriasis.² Sánchez Regaña et al reported women with plaque-type psoriasis vulgaris that worsened with development of prolactinomas, which subsequently improved with bromocriptine administration.³

Prolactin is a neuropeptide hormone produced by the anterior pituitary, known for its lactogenic, mammotrophic, and reproductive effects. It is also produced by extrapituitary tissue (neurons, prostate, decidua, mammary epithelium, immunocompetent cells, skin, and hair follicles). Prolactin in vitro stimulates the proliferation of human keratinocytes. Additionally, prolactin acts as a proinflammatory cytokine, enhancing INF-γ, IL-12p40, and IL-1b production in murine peritoneal macrophages. Furthermore, IFN-γ and TNF-α production are noted in T cells and peripheral blood mononuclear cells. Hau et al have demonstrated that intraperitoneal prolactin in mice enhances the expression of Th17 and Th1 cytokines/chemokines, thereby augmenting inflammation in imiquimod-induced psoriasiform skin. The authors concluded that prolactin may exacerbate psoriasis via the enhancement of Th17/Th1 responses.⁴

Increased levels of prolactin have been associated with psychoemotional stress.⁵ Multiple manuscripts have associated elevated serum prolactin levels with other autoimmune diseases including systemic lupus erythematosus, systemic sclerosis, Reiter's syndrome, rheumatoid arthritis, diabetes mellitus, Addison's disease, and autoimmune thyroiditis.⁶

There have been numerous studies in the literature measuring prolactin levels in patients with psoriasis, yielding conflicting data. Lee et al performed a meta-analysis comparing serum/plasma prolactin levels in patients with psoriasis with those of healthy controls and correlating circulating prolactin to psoriasis severity based on the Psoriasis Area and Severity Index (PASI). In total, 12 studies assessing 446 patients with psoriasis and 401 healthy controls were included. Prolactin levels were significantly higher in the psoriasis group than in the control group (P < .01). Stratification by age and gender also revealed a significantly higher prolactin level in the psoriasis group (P < .01). Subgroup analysis by sample size showed a significantly higher prolactin level with larger sample sizes (n ≥80; P = .02), but not with smaller sample sizes (n <80) in the psoriasis group. Meta-analysis of the correlation coefficients showed a positive, although not statistically significant, correlation between circulating prolactin and PASI (P = .08). The authors concluded that circulating prolactin levels are higher in patients with psoriasis, and prolactin levels may correlate with psoriasis severity.⁷

More research is warranted in unraveling the mysterious relationship among nerves, hormones, inflammatory cells, and skin. Prolactin may be an integral piece of the puzzle. Solving this riddle will inevitably lead to novel therapeutic interventions for psoriasis and other autoimmune disorders aggravated by stress. In the meanwhile, turning off cable news and listening to classical music might help!

Disclaimer: First published on Dr. Warren Heymann's Dermatology Insights and Inquiries website on September 18, 2017. Republished with permission.

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Benjamin Hidalgo-Matlock

Skin Care Physicians of Costa Rica

4000-1054

2101-9574

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