Selenium Sulfide - Indications, Directions for Use, and Mechanism of Action

Overview

Selenium sulfide is a sulfide salt that contains covalently bonded Selenium molecules. It is an anti-infective (antifungal) and antiseborrheic agent which is used as a topical (external use only) preparation to treat seborrheic dermatitis. FDA (The United States Food and Drug Administration) has identified Selenium sulfide as a safe drug and approved it on 1st September 1983. Under the Federal Food, Drug, and Cosmetic Act, FDA has placed Selenium sulfide in the orange book (list of Approved Drug Products With Therapeutic Equivalence Evaluations) based on the safety and effectiveness of the drug. It is an active ingredient in the preparation of medicated shampoos and lotions of various strengths. Selenium sulfide exhibits toxic effects on ingestion and inhalation.

What Are the Indications for Using Selenium Sulfide?

The use of Selenium sulfide has been indicated in various fungal as well as inflammatory skin infections and diseases. Some of its indications are as follows -

• Seborrheic dermatitis.

• Dandruff (white, dry flakes on the skin of the scalp).

• Fungal infections.

• Pityriasis versicolor (tinea versicolor).

• Papillomatosis (both confluent and reticulated types).

• Tinea capitis (it is used as an adjuvant with Griseofulvin).

• Hyperkeratosis (excessive thickening of the epidermal layer of the skin).

• Veterinary use (topical treatment for eczema and dermatomycoses).

Therapeutic uses of Selenium Sulfide

• Selenium sulfide is used as an antifungal agent to treat fungal infections like tinea capitis that primarily occurs in preadolescent children.

• It is an effective cytostatic agent that slows down the growth of hyperproliferative cells that occurs in seborrheic dermatitis.

• Selenium sulfide is used as an active ingredient in medicated shampoos for treating various conditions such as dandruff and seborrheic dermatitis.

• Topical application of Selenium sulfide is used to treat pityriasis versicolor.

What Is the Dosage and Mode of Administration of Selenium Sulfide?

The medicated form of Selenium sulfide is liquid preparation (shampoo and lotion) in different strengths. It is only for topical application (external uses only).

• 2.5 % Lotion (Available Only by Prescription) - Controls dandruff and seborrheic dermatitis of the scalp.

• 1 % Selenium Sulfide (Available Over the Counter) - Relieves itchiness and flaking of the scalp that occurs due to dandruff

• 0.6 % Micronized Form - It is safe and effective for dandruff due to seborrheic dermatitis.

Product Categories of Selenium Sulfide

• Shampoo (Personal Hair Care) - 1 % Selenium sulfide (207, 325, 400, 420 mL).

• Anti-dandruff agent.

• Cleansing agent.

• Humectant (retains moisture).

• Hair Conditioning Agent -1 % Selenium sulfide (207, 325, 400, and 420 mL).

• Hair softener.

• Lotion - 2.5 % Selenium sulfide (120 mL).

Administration for Seborrheic Dermatitis

• 5 to 10 mL of shampoo is massaged on a wet scalp and left for two to three minutes, followed by thorough rinsing.

• This procedure is repeated twice weekly for two weeks.

• Maintenance Use - Once weekly for every one to four weeks.

• Recommended Age Group - Adults and children above two years of age.

Benefits of Shampooing for Seborrheic Dermatitis

• Effective cleansing agents for scalp and hair.

• Removes sebum (oily layer) and foreign residues from the hair’s surface.

• Acts as a humectant (retaining moisture).

• Maintains the pH of the scalp by neutralizing alkalinity.

• Prevents dryness and seborrhea.

• Inhibits the growth of microorganisms (Malassezia spp. and Propionibacterium spp.) that cause skin infections on the scalp.

• Has antifungal properties.

Contraindications

• Its use is contraindicated in children less than two years of age since the safety of Selenium sulfide in infants has not yet been studied and documented.

• In pregnant women, its use is avoided due to the lack of supporting evidence.

• Hypersensitivity to Selenium sulfide and also the active ingredients present in the medicated preparations.

• Inflamed skin and skin with open wounds.

For Patients

What Is Seborrheic Dermatitis?

Seborrheic dermatitis is an inflammatory skin disorder that affects the areas with prominent sebaceous glands (glands containing oily substances), such as the head and the trunk (chest, abdomen, back, and pelvis). The reason for the occurrence of seborrheic dermatitis is not defined clearly. Research studies have identified various predisposing factors for its clinical prevalence. Some of the causative factors are as follows,

• Growth of fungus (lipophilic yeasts of the Malassezia genus).

• Genetic factors (not inherited).

• Hormonal imbalance.

• Environmental factors.

Who Is Affected by Seborrheic Dermatitis?

Seborrheic dermatitis affects two to five percent of the general population of all age groups and has no gender predominance. However, there is an increased incidence of certain conditions like

• Post puberty due to hormonal changes (androgen stimulation).

• Neonates due to maternal hormone stimulation (disappears in six to 12 months of age).

• Patients with acquired immunodeficiency syndrome.

• Individuals with central nervous system dysfunction (Parkinson's disease, cranial nerve palsy, and major truncal paralysis).

What Are the Clinical Presentations of Seborrheic Dermatitis?

• In the scalp, it ranges from mild dandruff to diffuse, dense, and adherent scales.

• In the face and trunk, it is presented as powdery and greasy scales in the folds of the skin and along the margins of hair.

• Usually, pruritus is not seen (no itching).

• Scalp lesion in infants (cradle cap).

• Other areas include eyebrows, ears, nasolabial folds, ears, chest, pubic areas, and around the anus.

What Is Selenium Sulfide?

Selenium sulfide is an inorganic compound that comes under the class of dermatologic agents (pharmaceutical agents that are directly applied to the skin). It is available as 2.5 % lotion (prescription only) and one percent shampoo (over the counter). Currently, Selenium sulfide is indicated for the treatment of seborrheic dermatitis (especially scalp).

Selenium sulfide exhibits a cytostatic (prevent cell multiplication) effect on skin cells. This prevents the growth of fungi on the skin and reduces the fungal attachment to the skin. Selenium sulfide also prevents the maturation of fungal spores. It is applied on the skin, and there is no evidence of it being absorbed into the skin and entering the bloodstream. However, it should not be applied on abraded skin or skin injuries that are open.

What Are the Directions for Use?

• Recommended use for adults and children above the age of five years.

• This product should be used twice a week for two successive weeks.

• Followed by a maintenance procedure of once a week for the next successive two weeks.

• The hair has to be thoroughly wet before shampoo is applied.

• It should be left in contact with the scalp for two to three minutes.

• After this duration, it should be rinsed out thoroughly (to minimize hair discoloration and avoid side effects).

What Are the Precautions to Be Followed?

• Selenium sulfide shampoos and lotions should not be applied on broken skin or inflamed skin surfaces.

• Avoid daily shampooing and follow only the prescribed protocol.

• Always test the medication on a small patch of skin (preferably on the dorsal surface of the palm or elbow) before the first wash to prevent allergy or hypersensitivity.

• Contact with eyes has to be avoided.

• Contact with the jewelry should be avoided. It is advised to remove metal ornaments while using the Selenium sulfide shampoo.

• Individuals who have sensitive skin must inform the doctor prior to prescription.

• Care has to be taken to prevent accidental intake, especially in children.

• Accidental ingestion has to be reported immediately.

• It should be kept out of reach of children and pets.

• It is stored in a dry, cool place to avoid sunlight.

• Moisture could interfere with its chemical properties, so avoid keeping it inside wet bathrooms.

• After using, close the lid tightly to prevent water from entering the container.

• Freezing should be avoided.

• In case of prolonged irritation to the eyes, allergic reactions, or hypersensitivity, report to the doctor immediately.

• Selenium causes discoloration of hair which is minimized by the thorough washing out of the product.

• In case of missing a dose in a week, continue with the regular dose next week. Do not use an excessive amount of shampoo in the next wash.

• If any adverse reactions or failure to improve in clinical symptoms, report to the doctor immediately. Do not discontinue as per will.

• In case of recurrence, consult the doctor before starting its usage.

What Are the Side Effects of Selenium Sulfide?

No serious side effects have been documented from the use of Selenium sulfide. Its safety and prescription protocols are under continuous surveillance by the FDA. However, certain side effects are seen in over-usage or excessive administration. Most of them could be avoided by following precautionary methods. Also, these reactions are only transient, and they fade away upon discontinuing the use. Some of the side effects include

• Skin irritation.

• Allergy.

• Irritation to the eyes.

• Discoloration of hair.

• Temporary hair loss.

• Itching in case of hypersensitive skin.

• Red-brown discoloration of the scalp.

• Changes in hair texture.

• Dryness of hair.

• Itchiness in the scalp and eyes.

For Doctors

Pharmacodynamics

Selenium sulfide is a dermatologic agent used in shampoos and lotions to treat seborrheic dermatitis and dandruff. It is an antifungal agent and actively inhibits the growth of the Malassezia genus. Selenium sulfide is a well-established cytostatic agent that slows down the growth of hyperproliferative as well as normal cells in seborrheic dermatitis and dandruff. The antiseborrheic effect of Selenium sulfide is due to the cytostatic effect on the cells in the epidermis and follicular epithelium.

Mechanism of Action

• Selenium sulfide inhibits mitotic cell division of epidermal and follicular epithelial cells.

• This phenomenon reduces fungal adhesion to corneocytes and favors the shedding of fungi and their spores from the stratum corneum.

• It causes the removal of the stratum corneum, which is eventually followed by the regeneration of a new healthy skin layer.

• Its antimitotic property results in reduced turnover of epidermal cells.

• Its mild local irritant, antifungal, and antibacterial properties contribute to its effectiveness.

• Its antifungal susceptibility spectrum includes Malassezia furfur, Trichophyton sp., and Microsporum sp.

• Selenium sulfide expresses its antifungal activity by decreasing the colonization by lipophilic yeast on the skin surface.

Chemical Taxonomy of Selenium Sulfide

Pharmacokinetics

When directly applied to the skin, Selenium sulfide is absorbed into the epithelial tissue and is converted into Selenium and sulfide ions. These Selenium ions block the enzyme complexes that facilitate epithelial cell growth. Thus Selenium sulfide decreases the rate of epithelial cell turnover (antimitotic property).

Selenium sulfide does not enter the bloodstream from intact skin. Absorption is only reported in individuals with open lesions. No detectable levels of Selenium sulfide in blood and urine in the recommended topical courses.

Selenium sulfide is a bright orange-colored powder. It is incorporated as an active ingredient in medicated shampoos. It is soluble in acids and insoluble in water and organic solvents. It decomposes on heating above 100 degrees centigrades and emits toxic fumes. It is toxic during inhalation and ingestion.

Drug Toxicity and Warnings

Potential routes of exposure are dermal contact and inhalation. The drug can be absorbed percutaneously when applied to damaged skin, and systemic toxicity may occur. Also, studies show that Selenium sulfide has human carcinogenic effects.

• Irritation of skin, eye, and mucous membrane.

• Development of orange to reddish brown discoloration of the scalp.

• Potential toxicity on ingestion and inhalation.

• Accidental ingestion causes diarrhea and gastrointestinal hypermotility.

• Inhalation results in dyspnoea and somnolence (generalized depression activity).

• Contact with the eyes causes severe irritation and redness of the eyes.

• It is a potential carcinogen.

• Though there is no evidence of fetal toxicity, use in pregnant women is avoided and is prescribed only under precautionary measures.

• Prolonged use of Selenium sulfide increases hair loss, and alters the texture of hair making it dry and brittle.

• Hair discoloration occurs, and the scalp becomes dry and oily.

• There is a potential risk of systemic toxicity if selenium sulfide lotions are applied to damaged skin (open lesions, acute inflammation, exudation of the scalp).

• Cutaneous sensitization is also reported.

Conclusion

Selenium sulfide is an antifungal and antiseborrheic agent used in the treatment of seborrheic dermatitis and dandruff. Its antiseborrheic effect is due to antimitotic effects on skin cells. It is used topically. It is available as medicated shampoos and lotions. Some of its commercial forms are one percent shampoo for dandruff treatment and 2. 5 % shampoo and lotions for seborrheic dermatitis treatment. Selenium sulfide is found to be effective and is widely recommended for the treatment of seborrheic dermatitis.