Azelaic Acid

Azelaic acid is a saturated nine-carbon dicarboxylic acid that occurs naturally in wheat, rye and barley and is produced by the skin yeast Malassezia. US products are Finacea Gel 15% (and generic azelaic acid gel 15%), Finacea Foam 15% and Azelex Cream 20%. Lake Hills Pharmacy uses azelaic acid in compounded topical preparations.

• Finacea Gel 15% and Foam 15%: topical treatment of the inflammatory papules and pustules of mild to moderate rosacea.
• Azelex Cream 20%: topical treatment of mild to moderate inflammatory acne vulgaris.
• Prescribers use compounded azelaic acid, alone or combined with other agents, for acne, rosacea, melasma, post-inflammatory hyperpigmentation and other hyperpigmentation disorders.

Azelaic acid has several actions: it is antibacterial against Cutibacterium acnes and Staphylococcus epidermidis by inhibiting microbial protein synthesis; it normalizes keratinization and reduces follicular hyperkeratosis; it reduces reactive oxygen species from neutrophils and dampens the kallikrein-cathelicidin pathway implicated in rosacea; and it competitively inhibits tyrosinase and has an antiproliferative effect on hyperactive melanocytes, with little effect on normal melanocytes. The exact mechanism in rosacea is not fully known.

A small fraction, a few percent, of a topical dose is absorbed through the skin. Absorbed azelaic acid is excreted mainly unchanged in the urine, with some undergoing beta-oxidation. Its apparent half-life after topical application is longer than after oral dosing because absorption is rate-limiting. Plasma levels after topical use remain within the range seen from normal dietary intake.

Azelex Cream labeling contraindicates use in patients with hypersensitivity to any of its components; Finacea labeling lists no contraindications. Compounded preparations should not be used in patients with hypersensitivity to azelaic acid or any component.

• Skin reactions: burning, stinging, itching, dryness and erythema are common, mostly early in treatment; stop if severe or persistent.
• Hypopigmentation has been reported; monitor patients with darker complexions for early signs.
• Avoid contact with the eyes, mouth and other mucous membranes; rinse with water if contact occurs.
• Worsening of asthma has been reported in patients using azelaic acid products.
• Finacea Foam contains a flammable propellant; avoid fire, flame and smoking during and right after application.

No formal interaction studies exist and no clinically relevant systemic interactions are expected with topical use. Irritation can be additive with retinoids, benzoyl peroxide, abrasive or drying cleansers and alcohol-containing products.

Burning, stinging, tingling, itching, dryness, erythema, scaling and contact dermatitis. Less often: hypopigmentation, hypersensitivity reactions including angioedema and urticaria, eye irritation after accidental contact, and worsening of asthma.

Systemic absorption after topical use is minimal. In animal studies, oral doses far above human topical exposure caused embryotoxicity only at maternally toxic levels, with no teratogenicity. Human data are limited. Azelaic acid is not expected to raise milk levels meaningfully above those from diet after topical use; avoid application to the breast area while nursing.

Tolerability and skin irritation, pigmentary changes in patients with darker skin, asthma symptoms in patients with asthma, and clinical response at follow-up.

• Finacea (azelaic acid) Gel 15% Prescribing Information, LEO Pharma.
• Finacea (azelaic acid) Foam 15% Prescribing Information, LEO Pharma.
• Azelex (azelaic acid) Cream 20% Prescribing Information.
• Guidelines of Care for the Management of Acne Vulgaris (2024), American Academy of Dermatology.