Atopic dermatitis (AD) is a very common inflammatory, genetic skin disorder that occurs more frequently in children. Its exact etiology is not known but it is characterized by pruritic skin reactions with elevation in the levels of inflammatory markers. Corticosteroids are the first line and the mainstay therapy in management of atopic dermatitis but have many local and systemic adverse effects. The study aims to evaluate the efficacy and safety of topical tacrolimus ointment in comparison to topical hydrocortisone cream in management of children diagnosed with atopic dermatitis.

Atopic dermatitis is a common pruritic inflammatory skin disorder. The prevalence of atopic dermatitis increased in the last three decades by two or three folds worldwide. In the developed countries, atopic dermatitis is estimated to affect 15% to 30% of children and 2% to 10% of adults. This type of dermatitis is usually associated with family history of other atopic disorders such as allergic rhinitis or asthma.

The clinical presentation of Atopic dermatitis differs depending on the age of the patient, it usually begins in infancy with erythematous, papular skin rash that may first appear on the cheeks and chin. In childhood, the skin appears dry, flaky, rough, cracked, and may bleed because of scratching, in adults the lesions are more diffuse with underlying erythema.

This condition is characterized by acute phase where the skin has red scaly patches and chronic phase in which the skin thickens.

Atopic dermatitis is a complex genetic disease where the exact etiology is not entirely known, but it is most probably due to interaction between environmental and genetic factors. The two major groups of involved genes are the genes encoding for epidermal and epithelial structural proteins and the genes regulating the production of cytokines for the immune response.

In atopic dermatitis patients, imbalance occurs between T helper-1 (TH1) and T helper-2 (TH2) immune responses, increased TH2 activity causes the release of interleukin (IL)-3, IL-4, IL-5, IL-10, and IL-13 which results in blood eosinophilia, increased total serum immunoglobulin (Ig) E, and increased growth and development of mast cells.

Atopic dermatitis patients are more likely to develop different skin infections as compared to healthy individuals, including: staphylococcal secondary bacterial infections and herpes simplex viral infection.

Topical corticosteroids (TCS) are the mainstay for management of atopic dermatitis to which other treatments are compared, they act by many pathways to reduce inflammation. Although TCS are effective treatment, they have both local adverse effects as skin thinning, striae, perioral dermatitis, acne, rosacea, telangiectasias, purpura and focal hypertrichosis. Moreover, systemic absorption can lead to systemic effects such as hypothalamic-pituitary-adrenal (HPA) axis suppression, infections, hyperglycemia, cataracts, glaucoma, and growth retardation (in children).

All these side effects are more likely to occur with prolonged use and so seeking for other treatment options is crucial.

Topical calcineurin inhibitors (TCI) as tacrolimus and pimecrolimus are immunosuppressives that help to control the acute flares and decrease the severity of the new flares by acting as immunomodulators. They inhibit the calcineurin so inhibit the T-cell proliferation that produces many inflammatory cytokines such as IL-2, IL-3, IL-4, IL-17, tumor necrosis factor (TNF). TCI is more selective as compared to TCS with less adverse effects so it is considered as an acceptable alternative to TCS.

Tacrolimus 0.03% ointment is approved for moderate to severe atopic dermatitis for ages 2 years and older, with the 0.1% ointment limited to ages 16 years and older; pimecrolimus 1% cream is approved for mild-to-moderate atopic dermatitis for ages 2 years and older. There is limited data comparing TCS with tacrolimus or pimecrolimus.

The FDA has a black box warning for both tacrolimus ointment and pimecrolimus cream about their potential local skin carcinogenesis as seen in animal studies. However, till now there is no causal relationship has been proven between use of a TCI and the development of lymphoma or non-melanoma skin cancer.

This study aims to assess the efficacy and safety of topical tacrolimus ointment in comparison to topical hydrocortisone cream in children diagnosed with atopic dermatitis. The primary outcome is to evaluate the effect of topical tacrolimus ointment as compared to topical hydrocortisone cream by estimation of the serum level of inflammatory cytokines and the effect on the dermatitis severity scale. The secondary outcome is to evaluate the tacrolimus safety as compared to hydrocortisone through the assessment of treatment related toxicities.

Inclusion Criteria:

• Male or female patients
• 2-16 years old
• diagnosed with Atopic Dermatitis according to Hanifin and Rajka criteria

Exclusion Criteria:

• patients with serious skin disorder other than Atopic Dermatitis
• patients taking systemic corticosteroids or anti-inflammatory medications.

200 opaque envelopes will be numbered serially and the corresponding letter which denotes the allocation will be put according to the electronic randomization table. Then all envelopes will be closed and put in one box. When the first patient arrives, the envelope will be opened and the patient will be allocated according to the letter inside.