Scalp dermatitis




1: Scalp dermatitis


Reid A. Waldman, Jane M. Grant-Kels


Abstract:



Scalp rashes are common and bothersome to patients. Scalp rashes have a broad differential diagnosis; accurate diagnosis is important because these conditions may lead to permanent hair loss. Additionally, several infections localize to the scalp and can flare if they are inappropriately treated with topical corticosteroids. This chapter will review scalp psoriasis, seborrheic dermatitis, lichen planopilaris, head lice, allergic contact dermatitis of the scalp, tinea capitis, and actinic keratosis, as well as their mimickers.

Key terms:


psoriasis


seborrheic dermatitis


lichen planopilaris


head lice


pediculosis capitis


allergic contact dermatitis


tinea capitis


actinic keratosis



Scalp psoriasis


Clinical features


Scalp psoriasis is characterized by the presence of well-demarcated erythematous plaques with overlying white scale of variable thickness affecting the occipital scalp more commonly than the remainder of the scalp.




Work-up




Initial steps in management


General management comments





Recommended initial regimen




What to do if there is a partial but inadequate response after a 4-week trial of potent topical corticosteroid monotherapy:



What to do if the response continues to be inadequate:



Other treatment options




Warning signs/common pitfalls




Counseling


Psoriasis is a rash that results from your genetics (family history) and immune system causing inflammation in your skin. Psoriasis is a chronic disease that tends to wax and wane. It is incurable, meaning that it lasts for years. Treatments for psoriasis are directed at decreasing inflammation in the skin. The goal of treating psoriasis is to manage symptoms.


Importantly, some people with psoriasis also develop a condition called psoriatic arthritis where they experience painful swelling of the joints and stiffness in the joints when they wake up in the morning that lasts for hours. If you think you may have psoriatic arthritis, it is important that you let us know because psoriatic arthritis can irreversibly damage your joints if it is not treated.


Some patients with psoriasis are at risk for metabolic syndrome (diabetes, obesity, cardiovascular disease, etc.). Therefore weight control and exercise are important to include in your daily routine.


I have prescribed you a topical corticosteroid. You should apply this to your scalp every day while you have the rash. When no rash is present, you do not need to use this medication. It is okay to resume use of the medication when the rash comes back. The major side effect of this medication is that it can thin the skin and cause the blood vessels in the skin to dilate and become visible. This typically does not occur on the scalp but may occur if you use the medication more frequently than instructed or if you apply this medicine to other places on your body, such as your face.


Seborrheic dermatitis—scalp


Clinical features


Seborrheic dermatitis is characterized by the presence of poorly circumscribed, thin, pink plaques with an overlying greasy-looking scale that appear on the seborrheic areas of the body. Seborrheic dermatitis is on a continuum with dandruff because both impact seborrheic areas of the body. Dandruff, however, is limited to the scalp and presents with pruritus and scaling but not erythema. Seborrheic dermatitis can impact other seborrheic areas in addition to the scalp and demonstrates itching, scaling, and evidence of inflammation.



The etiology of seborrheic dermatitis is multifactorial and is likely because of a normal body yeast called Malassezia. If the immune system has a somewhat irregular response to Malassezia, it may result in this inflammatory condition. The disease is very common, impacting 1% to 5% of the population and including all races and sexes.


Differential diagnosis




Tinea capitis can be distinguished from seborrheic dermatitis because tinea capitis usually presents as a solitary, discrete plaque, has overlying alopecia, and predominantly has peripheral scaling rather than diffuse scaling. If there is concern that the patient may have tinea capitis, a KOH examination and fungal culture can distinguish tinea capitis from seborrheic dermatitis.


Testing and work-up




How to manage seborrheic dermatitis


Management of seborrheic dermatitis is divided into two phases: (1) an intensive initial treatment phase, which is followed by a (2) less intensive maintenance phase. There is no cure for seborrheic dermatitis. The course is chronic with waxing and waning. Failure to emphasize the importance of using a maintenance therapy virtually guarantees disease recurrence and patient dissatisfaction.




Recommended initial treatment regimen in adults





What to do if there is a partial but inadequate response after a 4-week trial of topical azole monotherapy:



What to do if response to azole monotherapy wanes over time:


Jul 22, 2021 | Posted by in Dermatology | Comments Off on Scalp dermatitis
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