Videodermoscopy does not enhance diagnosis of scalp contact dermatitis due to topical minoxidil

Allergic Contact Dermatitis to Topical Preparations Containing Minoxidil: A Systematic Review and Individual Participant Data Meta-Analysis

Topical minoxidil is generally well tolerated, yet there have been a few reports of allergic contact dermatitis (ACD) confirmed through patch testing. This systematic review and individual participant data meta-analysis sought to elucidate the primary allergens in patients exhibiting ACD in response to topical minoxidil formulations and to ascertain the appropriate testing concentrations and vehicles of minoxidil itself. A comprehensive search was conducted across the PubMed, Scopus, and Embase databases utilizing the keywords "minoxidil" and "contact dermatitis," or "contact allergy," or "contact eczema." Studies documenting ACD in patients using topical minoxidil confirmed by patch testing were deemed eligible. Our analysis included 46 studies encompassing 99 patients with patch-test-confirmed ACD to minoxidil-based topical treatments. The majority of these patients (93.9%) were exposed to minoxidil without additional active components. Minoxidil itself was identified as the primary allergen in 74.7% of the patients, with propylene glycol being the next most common allergen at 17.1%. Other allergens identified included estradiol, butylene glycol, methylchloroisothiazolinone/methylisothiazolinone, canrenone, and latanoprost. The most effective concentration was found to be 2% minoxidil in propylene glycol, which yielded a 100% positivity rate. The findings indicate that minoxidil is the predominant allergen in ACD reactions to its topical formulations, followed by propylene glycol. For the accurate diagnosis of ACD related to minoxidil, patch testing with 2% minoxidil in propylene glycol is recommended, as are separate tests for propylene glycol and other potential allergenic ingredients.

Diagnostic Accuracy of Trichoscopy in Inflammatory Scalp Diseases: A Systematic Review

BACKGROUND

The common inflammatory scalp diseases, such as psoriasis, seborrheic dermatitis, lichen planopilaris, discoid lupus erythematosus, contact dermatitis, or pemphigus may share similar clinical features.

OBJECTIVE

To identify and systematically review the available evidence on the accuracy of trichoscopy in inflammatory scalp disorders.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 58 articles were included in the analysis.

RESULTS

The following trichoscopy features were found to show the highest specificity for the respective diseases: in psoriasis: diffuse scaling, simple and twisted red loops, red dots and globules, and glomerular vessels; in seborrheic dermatitis: atypical vessels, thin arborizing vessels, and structureless red areas; in discoid lupus erythematosus: follicular plugs and erythema encircling follicles; in lichen planopilaris: milky red areas or fibrotic patches; in contact dermatitis: twisted red loops; in pemphigus foliaceus: white polygonal structures and serpentine vessels; in pemphigus vulgaris: red dots with whitish halo and lace-like vessels; and in dermatomyositis: lake-like vascular structures.

LIMITATIONS

Different nomenclature and variability in parameters, which were analyzed in different studies.

CONCLUSION

This systemic analysis indicates that trichoscopy may be used with high accuracy in the differential diagnosis of inflammatory scalp diseases.

Optical coherence tomography in diagnosis of inflammatory scalp disorders

BACKGROUND

The common inflammatory scalp disorders share similar clinical manifestations, and patient work up require invasive, undesirable diagnostic procedures like biopsy to ensure correct diagnosis. Optical coherence tomography (OCT) is a non-invasive high-resolution imaging modality that has found a valuable tool to assist in the diagnose and evaluation of different skin diseases.

OBJECTIVES

To describe the structural and vascular dynamic OCT (D-OCT) findings of inflammatory scalp disorders including scalp psoriasis, seborrhoeic dermatitis and contact dermatitis and to compare trichoscopy and OCT features.

METHODS

Subjects with diagnosis of seborrhoeic dermatitis, psoriasis or contact dermatitis were enrolled in this study. OCT scans were taken on involved scalp, and the same scalp regions were evaluated by trichoscopy and compared with healthy scalp.

RESULTS

A total of fourteen subjects (two healthy controls, four seborrhoeic dermatitis, five psoriasis and three contact dermatitis) participated. D-OCT imaging of vascular pattern in healthy scalp and the inflammatory scalp disorders were described. D-OCT images could enhance the clinician's ability to distinguish psoriasis from seborrhoeic dermatitis by objectively detect and assess red loop density. In scalp contact dermatitis, the vessels of the deep plexus were more dilated and fewer in number than those found in seborrhoeic dermatitis.

CONCLUSION

Dynamic OCT provides information that more clearly elucidates changes at the level of the superficial and deep plexuses without invasively interfering with superficial structures. In the context of inflammatory scalp disorders, this is useful to discern disorders with overlapping symptoms and minimize the use of invasive biopsies to diagnose.

Common Allergens Identified Based on Patch Test Results in Patients with Suspected Contact Dermatitis of the Scalp

BACKGROUND

Contact dermatitis of the scalp is common and might be caused by many chemicals including metals, ingredients of shampoos and conditioners, dyes, or other hair treatments. Eliciting a careful history and patch tests are necessary to identify the responsible allergen and prevent relapses.

OBJECTIVES

To identify allergens that may cause contact dermatitis of the scalp by reviewing patch test results.

METHODS

We reviewed the records of 1,015 patients referred for patch testing at the Dermatology Department of the University of Miami. A total of 226 patients (205 females and 21 males) with suspected scalp contact dermatitis were identified, and the patch test results and clinical data for those patients were analyzed. Most patients were referred for patch testing from a specialized hair clinic at our institution.

RESULTS

The most common allergens in our study population were nickel (23.8%), cobalt (21.0%), balsam of Peru (18.2%), fragrance mix (14.4%), carba mix (11.6%), and propylene glycol (PG) (8.8%). The majority of patients were females aged 40-59 years, and scalp itching or burning were reported as the most common symptom.

CONCLUSION

Frequent sources of allergens for metals include hair clasps, pins, and brushes, while frequent sources of allergens for preservatives, fragrance mix, and balsam of Peru include shampoos, conditioners, and hair gels. Frequent sources of allergens for PG include topical medications.

Three-dimensional multiphoton/optical coherence tomography for diagnostic applications in dermatology

A preliminary clinical trial using state-of-the-art multiphoton tomography (MPT) and optical coherence tomography (OCT) for three-dimensional (3D) multimodal in vivo imaging of normal skin, nevi, scars and pathologic skin lesions has been conducted. MPT enabled visualization of sub-cellular details with axial and transverse resolutions of <2 μm and <0.5 μm, respectively, from a volume of 0.35 × 0.35 × 0.2 mm(3) at a frame rate of 0.14 Hz (512 × 512 pixels). State-of-the-art OCT, operating at a center wavelength of 1300 nm, was capable of acquiring 3D images depicting the layered architecture of skin with axial and transverse resolutions ~8 μm and ~20 μm, respectively, from a volume of 7 × 3.5 × 1.5 mm(3) at a frame rate of 46 Hz (1024 × 1024 pixels). This study demonstrates the clinical diagnostic potential of MPT/OCT for pre-screening relatively large areas of skin using 3D OCT to identify suspicious regions at microscopic level and subsequently using high resolution MPT to obtain zoomed in, sub-cellular level information of the respective regions.