Dr. Karen Ann O’Neill – Dermatologist | Mississauga, ON

Dr. Karen Ann O'Neill is a dedicated Dermatologist specializing in the diagnosis and treatment of a wide array of conditions affecting the skin, hair, and nails in adult patients, and may see older children for certain conditions. Practicing at a dermatology clinic in Mississauga, ON, she is a key member of the local medical community. She provides comprehensive medical and surgical dermatological care for a wide variety of skin, hair, and nail conditions, including acne, eczema, psoriasis, and skin cancer detection. Her practice is committed to delivering evidence-based care in a comfortable, professional environment, utilizing modern diagnostic and therapeutic equipment.

Dr. O'Neill graduated with a Medical Degree from the University of Toronto in Canada. She has over 37 years of experience as a Dermatologist, having started her practice in 1987. She is recognized as a RCPSC Specialist by the College of Physicians and Surgeons of Ontario (CPSO), with license number 52625. Her extensive training and certification ensure she maintains the highest standards of dermatological care and adheres to the regulations set by the CPSO.

Her clinical philosophy centers on evidence-based skin care, patient education on skin health and prevention, early detection of skin cancers, and personalized treatment plans tailored to each patient's needs. Dr. O'Neill is dedicated to providing thorough, compassionate care to her patients in Mississauga. She communicates effectively in English and strives to empower her patients through education and collaborative decision-making for optimal skin health outcomes.

Dr. Karen O'Neill diagnoses and treats a wide range of skin, hair, and nail conditions, including:

Skin Cancers, Precancerous Lesions & Benign Growths

• Dysplastic Nevi (Atypical Moles): Moles that look different from common moles (larger, irregular borders, varied color) and may have a higher risk of developing into melanoma. Often require monitoring or biopsy.
• Lipomas: Benign tumors composed of fat tissue, usually soft, movable, and painless, located just beneath the skin.

Acne, Rosacea & Follicular Disorders

• Acne Vulgaris (Comedonal, Papulopustular, Nodulocystic): A common skin condition characterized by pimples, blackheads, whiteheads, and sometimes deeper cysts and nodules, occurring when hair follicles become clogged with oil and dead skin cells. Severity can vary.
• Folliculitis (Bacterial, Fungal, Non-infectious): Inflammation of hair follicles, often caused by infection (e.g., Staph aureus, Malassezia) or irritation, leading to itchy or painful bumps, sometimes with pustules.

Hair & Scalp Disorders

• Cicatricial Alopecia (Scarring Alopecia - e.g., Lichen Planopilaris, Frontal Fibrosing Alopecia, CCCA): A group of rare disorders that destroy hair follicles, replace them with scar tissue, and cause permanent hair loss. Examples include Lichen Planopilaris, Frontal Fibrosing Alopecia, and Central Centrifugal Cicatricial Alopecia.
• Telogen Effluvium: A type of temporary, diffuse hair shedding often triggered by significant stress, illness, surgery, nutritional deficiencies, or hormonal changes (e.g., postpartum).
• Traction Alopecia: Hair loss caused by prolonged or repetitive tension on the hair follicles, often due to tight hairstyles (braids, ponytails, extensions).

This list is not exhaustive. For personalized advice regarding your specific dermatological condition, please consult with Dr. Karen O'Neill.

• Treatment for Skin Infections (Bacterial, Fungal, Viral, Parasitic): Diagnosis and treatment of various skin infections, such as impetigo, cellulitis, erysipelas, ringworm (tinea), athlete's foot, nail fungus (onychomycosis), warts, molluscum contagiosum, herpes simplex/zoster, and scabies.
• Nail Disorder Treatment (Fungal Infections, Psoriasis, Lichen Planus, Ingrown Nails, Tumors): Diagnosis and management of conditions affecting the nails, including infections, inflammatory disorders (like nail psoriasis or lichen planus), structural abnormalities, ingrown nails, and benign or malignant nail unit tumors.
• Patch Testing for Allergic Contact Dermatitis (Standard & Expanded Panels): Diagnostic procedure to identify specific allergens causing contact dermatitis by applying small amounts of common (and sometimes occupational or specialized) allergens to the skin.
• Cyst Excision and Drainage of Abscesses: Surgical removal of various types of skin cysts (e.g., epidermoid, pilar) and incision and drainage for skin abscesses.
• Cosmetic Mole Removal & Skin Tag Removal: Removal of benign moles or skin tags for aesthetic reasons, typically after dermatoscopic confirmation that the lesion is not suspicious for cancer.
• Comprehensive Dermatological Consultation & Full Body Skin Examination: In-depth assessment of conditions affecting the skin, hair, and nails, including review of medical history, complete skin examination (including scalp, nails, and mucous membranes), diagnostic testing, and personalized treatment planning.
• Dermal Fillers (Hyaluronic Acid, Calcium Hydroxylapatite, PLLA) for Volume Restoration & Contouring: Injectable gels (e.g., Juvederm®, Restylane®, Radiesse®, Sculptra®) used to restore facial volume, smooth out static wrinkles and folds, enhance lip volume, and contour facial features.

Note: This list provides a general overview of medical and potentially some cosmetic services. Treatment plans are highly individualized. Discuss with Dr. O'Neill for care relevant to your specific condition. Coverage for services varies; medically necessary treatments are typically covered by provincial health plans, while cosmetic procedures are usually self-pay.

All medical and surgical services (if applicable) are provided in accordance with the standards of practice set by the College of Physicians and Surgeons of Ontario (CPSO) and relevant dermatological care guidelines. Contact the clinic or your referring physician regarding new patient intake and referral processes.

Dr. O'Neill practices at a dermatology clinic situated within a medical facility in Mississauga's Central Erin Mills neighborhood. The clinic is conveniently located near the Erin Meadows Community Centre, making it accessible for local residents. Public transit options include MiWay (Mississauga Transit), with stops nearby providing easy access for patients using bus services. The facility is wheelchair accessible, ensuring barrier-free access for all patients. Parking is available at or near the facility, providing convenient options for those arriving by car. The practice aims to offer a welcoming environment that accommodates diverse patient needs while maintaining high standards of dermatological care.

Are consultations and dermatological treatments with Dr. O'Neill, a Dermatologist, covered by Ontario Health Insurance Plan (OHIP) in ON?

Medically necessary consultations with a licensed Dermatologist like Dr. O'Neill, diagnostic procedures (e.g., skin biopsies), and treatments for provincially insured skin conditions (e.g., psoriasis, severe eczema, skin cancer, infections) are generally covered by Ontario Health Insurance Plan (OHIP) in ON when a referral from a family doctor is in place. Purely cosmetic procedures (e.g., Botox for wrinkles, most laser hair removal, fillers for aesthetic enhancement) are typically not covered and are self-pay. It's crucial to discuss coverage specifics for any proposed treatment with Dr. O'Neill's office or Ontario Health Insurance Plan (OHIP) beforehand, especially if there's a potential cosmetic component.

Do I need a referral to see Dr. O'Neill, a Dermatologist?

Yes, for medically necessary dermatological care covered by the provincial health plan, a referral from your family physician or another specialist (e.g., an ER doctor for an acute issue) is almost always required to see a Dermatologist such as Dr. O'Neill. This ensures coordinated care and that your visit is appropriate for specialist assessment. Some dermatologists may offer consultations for uninsured cosmetic services without a referral, but these would be a direct cost to you. Always check with the clinic regarding their specific referral policy.

If Dr. O'Neill recommends phototherapy, what does that involve?

Phototherapy, also known as light therapy, is a medical treatment where your skin is exposed to specific wavelengths of ultraviolet (UV) light under strict medical supervision. Dr. O'Neill might recommend it for conditions like psoriasis, eczema, vitiligo, or cutaneous T-cell lymphoma. Treatments are typically given 2-3 times a week in a specialized light cabinet or with a handheld device for smaller areas. The type of UV light (e.g., Narrowband UVB, PUVA) and treatment duration are carefully controlled. It works by reducing inflammation and slowing down the rapid growth of skin cells. You'll be given specific instructions, including eye protection.

What is the difference between a Dermatologist and an Esthetician?

A Dermatologist, like Dr. Dr. O'Neill, is a medical doctor (MD) who has completed medical school followed by several years of specialized residency training in dermatology. They are qualified to diagnose and treat over 3,000 diseases of the skin, hair, and nails, prescribe medications, perform surgical procedures (like skin cancer removal), and manage complex skin conditions. An Esthetician (or Aesthetician) is a skincare professional trained in cosmetic skin treatments and services that improve the appearance of the skin, such as facials, superficial chemical peels, microdermabrasion, waxing, and makeup application. They are not medical doctors and cannot diagnose skin diseases, prescribe medications, or perform medical or surgical procedures.

What are the general risks and benefits of cosmetic procedures Dr. O'Neill might offer?

The benefits of cosmetic procedures offered by a qualified Dermatologist like Dr. O'Neill can include improvement in skin appearance, texture, tone, reduction of wrinkles or scars, and enhanced self-confidence. However, all procedures carry some risks. Common risks for minimally invasive cosmetic treatments (like injectables or lasers) can include temporary redness, swelling, bruising, pain, or itching at the treatment site. Less common risks might include infection, allergic reaction, changes in skin pigmentation, or unsatisfactory results. More invasive procedures have different risk profiles. Dr. O'Neill will discuss the specific risks, benefits, and expected outcomes of any proposed cosmetic procedure in detail during your consultation to help you make an informed decision.

2145 Dunwin Drive
Mississauga, ON L5L 4L9

Phone: (905) 820-7546 | Fax: (905) 820-6665

The facility is wheelchair accessible.

Dr. O'Neill is a licensed Dermatologist regulated by the College of Physicians and Surgeons of Ontario (CPSO) under the Regulated Health Professions Act, 1991 and Medicine Act, 1991 in ON. A referral from a family physician is typically required for consultations with Dr. O'Neill for medically necessary services covered by the provincial health plan. Cosmetic consultations may have different requirements.

Verify registration with the College of Physicians and Surgeons of Ontario (CPSO): https://doctors.cpso.on.ca/DoctorDetails/ONeill-Karen-Ann/0038649-52625