What is Dandruff?
Tinea capitis and seborrheic dermatitis (dandruff) are scalp disorders characterized by scaling and itchiness related to fungal infection. Tinea capitis usually affects children and is spread by direct contact. The skin lesions appear as scaly patches on the scalp that are often associated with hair loss (alopecia). Lymph nodes in the head or neck may enlarge as a reaction to scalp infection, but usually resolve with clearance of infection. Learn more about causes and dandruff treatment by reading below.
Seborrheic dermatitis (dandruff), although technically not a fungal scalp infection, may produce symptoms that are similar to tinea capitis. This condition often affects infants, adolescents, and adults. Dandruff is implicated to be indirectly caused by Malassezia yeast – a type of fungus. In fact, dandruff usually responds well to certain antifungal shampoos.
What Causes Dandruff?
Tinea capitis is caused by contact of scalp hair with dermatophytes (a type of fungi). This may occur through direct contact with an infected person or animal, or by contact with objects such as combs and hats. Trichophyton and Microsporum are the most common fungi responsible for fungal scalp hair infection. These fungi lead to irritation and inflammation of scalp tissue and hair follicles – which causes itching, scaling, and hair loss in the region.
Seborrheic dermatitis (dandruff) is a chronic inflammatory skin condition that affects areas that are high in sebaceous glands such as the scalp and face. Although not technically a fungal scalp infection, there is strong indirect evidence that Malassezia yeast are involved in its pathogenesis. Furthermore, antifungal therapies are effective in the treatment of dandruff.
How Common is Dandruff?
Tinea capitis is a common condition that most often affects pre-pubertal children – adults may also occasionally acquire the disease. There appears to be a higher prevalence in males compared to females.
Seborrheic dermatitis can be seen in infants as well as adolescents and adults. Its prevalence is about 3% and peaks at age 30-40. Men are affected more than women. The condition also has a high prevalence in individuals infected with HIV.
Signs and Symptoms
Symptoms of tinea capitis often include scaly patches with areas of hair loss (alopecia). Hair loss often appears as black dots which represent broken hairs. Patients often have itchiness (pruritus) of the scalp and may develop enlarged tender lymph nodes (cervical lymphadenopathy) as a reaction to fungal scalp infection.
Seborrheic dermatitis typically causes a fine, white, scales on the scalp. In severe cases, the skin can be inflamed, with red plaques covered in yellow, greasy scales. These can be itchy and irritating.
Other conditions that are sometimes mistaken for tinea capitis or seborrheic dermatitis include psoriasis and eczema.
Tinea capitis is typically diagnosed based on symptoms and physical examination of the skin lesion. Your doctor may recommend a potassium hydroxide (KOH) preparation or fungal culture if the diagnosis is not clear. Sometimes they will examine the skin under Wood’s lamp to clarify the diagnosis.
The diagnosis of seborrheic dermatitis is also typically made based on symptoms and physical examination. Your dermatologist may recommend a skin biopsy if the diagnosis is in question.
Dandruff Treatment and Medication
Seborrheic dermatitis is typically treated with antifungal shampoos such as:
Alternative treatments include coal tar and salicylic acid. Shampoos are generally used 2-3 times per week for several weeks. Patients with itching and inflammation may benefit from a high potency corticosteroid shampoo, lotion, or foam such as Clobex (clobetasol proprionate). Long-term control of seborrheic dermatitis typically requires antifungal shampoo treatment once a week.
Tinea capitis generally requires oral antifungal therapy. The most commonly prescribed medications include:
- Gris-PEG (griseofulvin)
- Lamisil (terbinafine)
- Diflucan (fluconazole)
Patients and household members may also benefit from using antifungal shampoos as adjunctive therapy - these can decrease the spread of infection to others.
- Mirmirani P, Tucker LY. Epidemiologic trends in pediatric tinea capitis: a population-based study from Kaiser Permanente Northern California. J Am Acad Dermatol 2013; 69:916.
- Naldi L, Rebora A. Clinical practice. Seborrheic dermatitis. N Engl J Med 2009; 360:387.
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.