From the Guidelines
Scalp psoriasis is primarily caused by a genetic, systemic, inflammatory, and chronic disorder, which can be altered by environmental factors, as stated in the guidelines of care for the management of psoriasis and psoriatic arthritis 1. The exact trigger is unknown, but genetic factors play a significant role, with about one-third of patients having a family history of the condition. Environmental factors such as stress, skin injuries, certain medications (like beta-blockers and lithium), and infections (particularly streptococcal throat infections) can trigger or worsen scalp psoriasis. The immune system mistakenly attacks healthy skin cells, causing inflammation and accelerating the skin cell production cycle from the normal 3-4 weeks to just days. This rapid turnover prevents cells from maturing properly, resulting in the characteristic silvery scales and red, inflamed patches. Unlike dandruff, which causes small white flakes due to a yeast infection or dry skin, scalp psoriasis produces thicker, more adherent scales that may bleed when removed. Some key points to consider in the management of scalp psoriasis include:
- The use of vitamin D analogues, such as calcipotriene, which can inhibit keratinocyte proliferation and enhance keratinocyte differentiation 1.
- The effectiveness of treatment with calcipotriene foam for 8 weeks and calcipotriene plus betamethasone dipropionate gel for 4 to 12 weeks compared with placebo for the treatment of mild to moderate scalp psoriasis 1. The condition tends to be chronic with periods of flare-ups and remissions, and while not contagious, it can significantly impact quality of life through physical discomfort and psychological distress. Given the most recent evidence from 2021, the treatment of scalp psoriasis should prioritize the use of topical therapies, such as vitamin D analogues, and alternative medicine modalities, as recommended in the joint AAD-NPF guidelines of care for the management and treatment of psoriasis 1.
From the Research
Causes of Psoriasis of the Scalp
- Psoriasis is a chronic inflammatory skin disease that is identified by the appearance of erythematous, clearly demarcated, scaly plaques 2
- The etiopathogenesis of psoriasis is not yet fully understood, but it is considered an outcome of some alteration of the cells in the immune system, which fights infections, but here, it attacks healthy cells 2
- Researchers believe both environmental and genetic factors play a role in the development of psoriasis 2
- Changes in the skin microbiome may affect the immune system and skin barrier functions, thereby contributing to the development and progression of psoriasis 3
- A significant correlation was observed between increased mycobiome diversity and disease severity, suggesting a possible avenue for targeted therapeutic interventions 3
Role of the Microbiome in Scalp Psoriasis
- The scalp microbiome of patients with psoriasis complicated with scalp lesions was examined, and the results showed a higher abundance of Malassezia globosa in the severe group 3
- Pseudomonas and Staphylococcus were more prevalent in the moderate and severe groups than in the mild group 3
- The study highlights the potential role of increased fungal diversity and specific microbial compositions in the severity of scalp psoriasis 3