The aim of this study is to:

1. Evaluation of serum soluble intercellular adhesion molecule-1 (sICAM-1) level in acne vulgaris and compare it to control group
2. Evaluate its role in acne pathogenesis and its correlation with acne vulgaris severity
3. Evaluate the effect of Montelukast on serum (sICAM-1) level in acne vulgaris

Acne vulgaris is a common chronic skin disease involving blockage and inflammation of pilosebaceous units

. It is characterized by non-inflammatory, open or closed comedones and by inflammatory lesions include papules, pustules and nodules. Affecting mostly the face, but also the back and chest .

Acne vulgaris may have a psychological impact on any patient, regardless of the severity or the grade of the disease .

Prevalence of self-reported acne was 34.7%. Females significantly reported acne more frequently than males (39.1% vs. 30.3%) Prevalence of clinically confirmed acne was 24.4%, with higher rates among females (28.6%) than males (20.2%).

Its pathogenesis result from increased sebum production (due to increased activity of androgens and insulin growth factor-1), excessive deposition of keratin in pilosebaceous follicles leading to comedo formation, colonization of the follicle by Propionibacterium acnes bacteria, and the local release of pro-inflammatory chemicals in the skin through certain inflammatory mechanisms.

Recently, Inflammation is a key feature in the pathogenesis of acne vulgaris, with various chemokines and cytokines that contribute to fuel a vicious cycle .

Leukotriene B4 (LT-B4) is the most potent leucocyte chemotactic mediator in the pathogenesis of acne . Intercellular adhesion molecule-1 (ICAM-1) is a transmembrane glycoprotein in the immunoglobulin superfamily that increases in response to various inflammation mediator, In addition, genetics is also a key factor in the pathophysiology of acne .

There are various topical therapies for acne vulgaris including topical retinoids, antimicrobials, benzoyl peroxide, salicylic acid, lactic acid, dapsone and niacinamide. Moderate to severe acne is treated with oral antibiotics, especially tetracyclines, and isotretinoin is prescribed for severe acne unresponsive to antibiotics.

Montelukast is an antagonist of LT-B4 receptor . Montelukast has good efficacy, tolerability, and safety in the treatment of acne.

Inclusion Criteria:

• Healthy persons of both sexes with moderate and severe acne vulgaris.
• Patients age between 15-35 years
• Patients with acne vulgaris not receiving any topical or systemic treatments for acne at least 2 weeks and 2 month before the study ,respectively

Exclusion Criteria:

• Pregnant and lactating women
• Diabetics
• Hypertensive patients
• acne conglobate patients and acne fulminans patients
• patients with history of polycystic ovaries syndrome
• Patients with history of thyroid dysfunction
• Patients with history of chronic inflammatory or immune-mediated diseases as Crohn's disease, vascular dementia, systemic sclerosis, systemic lupus erythematosus, ankylosing spondylitis, psoriatic arthritis and SAPHO syndrome.
• Any history of hypersensitivity reaction to the studied drug