Key differences
- Seborrheic dermatitis is a type of chronic inflammatory skin condition that leads to a rash, while seborrheic keratosis is a non-cancerous (benign) skin growth.
- Seborrheic dermatitis typically results in red areas covered by greasy scales. Seborrheic keratosis usually presents as rough, warty raised growths.
- Seborrheic dermatitis is commonly seen in areas that are rich in sebaceous (oil) glands while seborrheic keratosis does not have the same distribution pattern.
- Seborrheic dermatitis is more common in adolescents and adults, while seborrheic keratosis is usually seen in middle-aged and older adults.
- Seborrheic dermatitis is often treated with antifungal medications and, in some cases, steroids. Seborrheic keratosis usually doesn’t require treatment unless it becomes symptomatic, changes in appearance, or is bothersome for cosmetic reasons.
Read the detailed comparison of seborrheic dermatitis and seborrheic keratosis below, along with their pictures, causes, and treatment options.
What are they?
Seborrheic dermatitis: This is a chronic, inflammatory skin condition that results in a rash. It primarily affects the scalp, face, and upper body and is often seen in adolescents and adults. A person may experience frequent flare-ups of the condition.
Seborrheic keratosis (SK): This is a non-cancerous skin growth that commonly appears in middle-aged and older adults. The number of SKs can increase with age.
Appearance
Seborrheic dermatitis
Seborrheic dermatitis leads to inflamed and red patches on the skin. In some cases, they can be raised to form thin red plaques. These areas have overlying greasy-looking scales that can be white, yellowish, or gray.
It is commonly seen in areas rich in sebaceous glands, such as the scalp, eyebrows, and sides of the nose.
Seborrheic keratosis
These growths have a characteristic ‘stuck-on’ or ‘pasted-on’ appearance (this is the reason they are often called skin barnacles).
These lesions are commonly pigmented and brown, but they can also be white, tan, gray, skin-colored, or pink. They may be flat but are often elevated to form papules or plaques on the skin. They may appear waxy or warty and can be a small spot of a few mm or a larger spot several cm in size.
Unlike seborrheic dermatitis, seborrheic keratosis is not distributed in oil-rich areas and can occur anywhere except the palms, soles, and mucous membranes.
Pictures
Associated symptoms
Seborrheic dermatitis may be associated with itching, burning, or discomfort. On the other hand, seborrheic keratoses are usually asymptomatic but can become itchy, especially if rubbed frequently. Sometimes, they may become inflamed.
Contagious
Both seborrheic dermatitis and seborrheic keratoses are not contagious, so they cannot spread by touching.
Causes
The exact cause of seborrheic dermatitis is unclear, but it is associated with the overgrowth of yeast Malassezia on the skin, excessive oiliness, skin barrier defects, genetics, and neurogenic factors. It’s important to note that Malassezia is part of the normal skin flora, and why it overgrows in some individuals is not completely understood.
The exact cause behind seborrheic keratosis is also unknown. It is thought to be associated with aging, sun exposure, and genetic factors.
Relation to cancer
Both seborrheic dermatitis and seborrheic keratosis are not cancers. However, the sudden appearance of multiple seborrheic keratoses, or a rapid increase in the size or number of existing ones, may be associated with an underlying malignancy. This is known as the sign of Leser-Trélat.
So, in such a case, one should see a doctor to rule out any other underlying cause.
Diagnosis
Seborrheic dermatitis
It is usually diagnosed based on its symptoms and physical examination by a doctor. If necessary, skin scrapings may be taken to rule out a fungal infection. A biopsy is seldom required.
Seborrheic keratosis
It can also be diagnosed based on its characteristic appearance. However, pigmented and inflamed seborrheic keratosis can resemble skin cancers like melanoma and squamous cell carcinoma.
In such cases, your doctor may recommend a biopsy or excision of the lesion. The tissue is often sent to a pathology lab where it is examined under a microscope to confirm the diagnosis.
Treatment
Seborrheic dermatitis
Seborrheic dermatitis is a chronic condition, so it cannot be cured but can be managed with effective treatments.
- Shampoos containing antifungal ingredients that decrease Malassezia (such as pyrithione zinc, and ketoconazole) or keratolytic (such as salicylic acid, and coal tar) that decrease the buildup of dead skin cells are often used to control symptoms.
- Antifungal creams can be prescribed that are effective against the yeast.
- Low-potency corticosteroid creams can reduce inflammation and control itching but should not be used for extended periods due to potential side effects.
- Topical calcineurin inhibitors like tacrolimus or pimecrolimus can be recommended in some cases.
- In severe cases, oral antifungals or steroids may be prescribed.
Seborrheic keratosis
Seborrheic keratosis does not require treatment but can be treated for cosmetic reasons or if the lesion becomes irritated. Treatment options include:
- Cryotherapy: This method involves freezing the growth with liquid nitrogen, which can destroy the skin growth and cause it to fall off.
- Curettage: The growth is scooped out with a curette.
- Electrocautery: This involves burning the growth with an electric current. It is often combined with curettage to scrape off the treated growth.
- Excision: Larger growths may be excised.
- Laser: This is a non-surgical option for removal.
- Topicals: There are several topicals that can be used, but results may vary.
Prevention
Seborrheic keratosis: There’s no known effective method for prevention, given that the primary factors are age and genetics.
Seborrheic dermatitis: While one cannot prevent seborrheic dermatitis, the following measures may reduce flare episodes:
- Stress management.
- Wash the affected area with an antifungal wash or shampoo a few times a week.
- Follow the treatment plan recommended by your doctor.
- Avoid skin irritants.
Takeaway
Seborrheic dermatitis and seborrheic keratoses are often confused due to similarities in their names. However, both these conditions look completely different and are managed differently.
If you’re unsure about the cause of your skin lesion, it’s best to consult a doctor for diagnosis and appropriate treatment.
References
- Mansur AT, Yildiz S. A diagnostic challenge: inflamed and pigmented seborrheic keratosis. Clinical, dermoscopic, and histopathological correlation. Dermatol Online J. 2019 Mar 15;25(3):13030/qt0w56m5hq. PMID: 30982311.
- Dall’Oglio F, Nasca MR, Gerbino C, Micali G. An Overview of the Diagnosis and Management of Seborrheic Dermatitis. Clin Cosmet Investig Dermatol. 2022 Aug 6;15:1537-1548. doi: 10.2147/CCID.S284671. PMID: 35967915; PMCID: PMC9365318.
Disclaimer: This article is for information purposes only and does not replace medical advice.