One of the most common forms of dermatitis is eczema, which occurs more in children than adults. This skin condition presents as dry, itchy skin that leads to rashes due to itching, rubbing and irritation. When the person continues to itch and rub their skin, the skin will thicken causing lichenification. Genetic, environmental and lifestyle factors play a role in this condition. A common gene mutation observed in atopic dermatitis is Filaggrin, which is responsible for making the skin’s outer layer by forming corneocytes. People with eczema have a dysfunctional and unorganized skin barrier which causes dry skin since there is water and moisture loss. In addition, they have a decreased number of beta-defensins, which are host defense peptides so they are more prone to infections. The damaged skin provides less protections against irritants, allergens, viruses and bacterias. They are more prone to Staphylococcus aureus infections which can make eczema worse and need to be treated with antibiotics. Eczema herpeticum, a medical emergency, can also occur caused by the ****** simplex virus-1. Treatment and management of eczema are skin hydration and topical anti-inflammatory medications. Moisturizing products such as emollients and ointments are used to hydrate the skin and keep it from drying out. Steroid creams or topical pimecrolimus and tacrolimus can be used to treat flare-ups. Topical steroids shouldn’t be used daily because there are numerous long term side effects including atrophy, telangiectasia and rebound dermatitis. Oral antihistamines can be taken at bedtime to help with disturbed sleep caused by itching. It is essential to educate patients on eliminating and avoiding triggers and allergens that might cause flare-ups.
References
Nemeth V, Evans J. Eczema. [Updated 2020 Mar 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538209/
InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Eczema: Overview. 2013 Sep 26 [Updated 2017 Feb 23].Available from: https://www.ncbi.nlm.nih.gov/books/NBK279399/
Eczema, Urticaria, and Other Skin Conditions
Atopic Dermatitis
Atopic dermatitis (AD), or eczema, is the most commonly occurring chronic skin condition with a prevalence of up to to 13% in the United States. The signs and symptoms of AD include dry skin, lesions and lichenification. AD is often comorbid with other chronic ‘allergic disorders’, such as asthma and food allergies. AD can also increase the likelihood of other IgE mediated conditions, such as allergic rhinitis (Kim J).
The pathophysiology is defined by immune dysregulation that impairs the skin barrier. AD can also be genetic, due to a mutation in fillagrin transglutaminase (FLG), which can compromise epidermal permeability, causing increased penetration of allergens and microbes. Additionally, genetic polymorphic changes in Interleukins (IL) can cause abnormal, overreactive inflammatory responses, thus further compromising the epidermal barrier. IL-4 and IL-13 are key immunomodulators in potentiating skin barrier dysfunction, and IL-31 is responsible for itchiness, which patients can experience with AD (Kim J, Kolb L).
Treatment for AD is comprised of four components: trigger avoidance, daily skin care, anti- inflammatory therapy, and complementary medicine. Trigger avoidance consists of avoiding allergens, such as using fragrance- free products and removing environmental triggers. Skin care involves using emollients two times a day to prevent skin drying. Topical steroids are first- line agents for anti- inflammatory therapy. They are used for treating flare- ups and then tapered and used as maintenance therapy for prevention. Side effects of topical steroid use include telangiectasia and skin atrophy with chronic use. Second line agents include topical calcineurin inhibitors, pimecrolimus and tacrolimus, and topical PDE-4 inhibitors, crisaborole. Uncontrolled AD can be treated using UV light phototherapy in combination with oral immunosuppressants. Monoclonal antibodies can also be used for patients with AD, with dupilumab being clinically indicated and approved for use. Complementary therapies include bleach baths, low allergen diets, and probiotic supplementation (Kolb L).
Urticaria
Urticaria is an allergic reaction known commonly as hives. It can be characterized as acute and self- resolving in less than 6 weeks, or chronic- lasting more than 6 weeks. Chronic urticaria can further be categorized as inducible or idiopathic based on history and exposure to triggers. Signs and symptoms of hives include wheals and pruritis, with or without localized or systemic edema. Chronic urticaria affects up to 2% of the population. The etiology is not fully defined, but it is believed to be IgE- mediated, which causes mast cell activation and release of histamine (Dabija D).
Urticaria management consists of identifying and avoiding triggers, as well as pharmacological management if indicated. First line agents are second- generation antihistamines, such as loratadine, cetirizine and fexofenadine. These agents are to be taken regularly for them to exert their antihistaminic effects. Second generation H1 blockers have a more tolerable side effect profile, causing minimal drowsiness, as compared to first generation agents. If a patient has inducible chronic urticaria, patients may take their antihistamine 2 to 4 hours before exposure to prevent the reaction, as opposed to idiopathic chronic urticaria. Other agents for chronic urticaria include omalizumab, which binds free IgE to mediate and decrease the reaction that causes the urticaria. Omalizumab is indicated when patients are unresponsive to antihistamines. For short flares of hives, systemic corticosteroids can be used to reduce symptom severity and flare duration. Topical steroids are not indicated in urticaria. Cyclosporine is a last line agent, due to its systemic toxicities, and is only used in patients that have refractory chronic urticaria and have failed antihistamine therapy (Dabija D).
Psoriasis
Psoriasis is an inflammatory condition that causes the erythematous and scaly plaques on the arms, scalp and back regions of the body. Psoriasis is chronic and waxes and wanes, with periods of flares and then improvement. Occurrence in the general population is up to 5% (Kim WB).
True etiology is unknown, but the genetic disease is mediated by T- lymphocytes and there is a strong association with HLA antigens. Activated T- lymphocytes trigger abnormal keratinocyte turnover, thus forming the thick plaques. Environmental factors, such as allergens and weather, and certain drugs can trigger flares in patients. Among others, chloroquine, lithium, beta-blockers, steroids, and NSAIDs can worsen psoriasis (Nair PA, Kim WB).
Management of psoriasis includes emollients and moisturizers, topical and systemic therapies, and phototherapy. Topical therapies include topical steroids and calcipotriene as monotherapies or in combination. Ultraviolet B (UVB) phototherapy is used in combination with oral immunosuppressants or alone. If UVB therapy is not available or cannot be used, oral immunosuppressants or biologics can be used. Approved biologics include adalimumab, etanercept, infliximab, and ustekinumab. With any immunosuppressant, including biologics, there is a risk of secondary infections. Second line therapies include combinations of UVB light and a biologic or methotrexate with a biologic (Kim WB).
Citations:
Dabija D, Tadi P, Danosos GN. Chronic Urticaria. [Updated 2023 Apr 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK555910/
Kim J, Kim BE, Leung DYM. Pathophysiology of atopic dermatitis: Clinical implications. Allergy Asthma Proc. 2019;40(2):84-92. doi:10.2500/aap.2019.40.4202
Kim WB, Jerome D, Yeung J. Diagnosis and management of psoriasis. Can Fam Physician. 2017;63(4):278-285.
Kolb L, Ferrer-Bruker SJ. Atopic Dermatitis. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448071/
Nair PA, Badri T. Psoriasis. [Updated 2023 Apr 3]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448194/