Atopic dermatitis

Question 1

Atopic dermatitis definition

Answer 1

An inflammatory skin disease characterized by pruritus and association with asthma and allergic rhinitis. Typical distribution is flexural lichenification in adults and facial and extensor involvement in children. The course is chronic or relapsing.
Hands including the wrists are frequently involved in adults, but other localized areas may involve ears, feet and breast

Question 2

Dennie-Morgan fold

Answer 2

A transverse fold line just below the edge of the lower lids, highly indicative of atopic dermatitis.

Question 3

Pytiriasis alba

Answer 3

Pityriasis alba (PA) is an eczematous dermatosis characterized by patchy hypopigmentation. It is usually seen in children, and is most noticeable in those with darkly pigmented skin, although it may occur in all skin types. The history will usually reveal worsening during the summer, as the contrast between normal and lesional skin becomes greater with sun exposure.

Question 4

Keratosis pilaris

Answer 4

Horny follicular lesions in the outer aspects of upper arms, legs, cheeks and buttocks (chicken skin bumps)

Question 5

Hertoghe’s sign

Answer 5

Thinning of lateral eyebrows from chronic rubbing

Question 6

Pompholix

Answer 6

Dyshidrosis or vesicular eczema of the palmar aspect of the hands

Question 7

Atopic dermatitis: determinant factors

Answer 7

Genetic factors
Immune factors: specially IL 4& 13, IL 31 (the itch cytokine), Janus kinase pathway, cyclic AMP and phosphodiesterase E4

Question 8

Topical therapies for atopic dermatitis

Answer 8

Emollients
Corticosteroids
Calcineurin inhibitors (effectiveness is comparable to low to mid potency steroids)
Crisaborole (mainly for mild cases)

Question 9

Systemic therapies for atopic dermatitis

Answer 9

Dupilumab (very effective biological, first line treatment in moderate to severe cases)
Prednisone (safe and effective but terrible long option)
Cyclosporine (fast and effective, but not good for more than 6 months)
MTX, MMF, azathioprine (slower response)
UV light usually as an adjuvant

Question 10

Systemic antihistaminics in atopic dermatitis

Answer 10

Only for sedation

Question 11

Numular eczema

Answer 11

More well demarcated than AD, more wet than psoriasis, can be triggered by allergic conditions, infections and irritant exposure

Question 12

Atopic dermatitis triggered by medications

Answer 12

May occur with calcium channel blockers and thizides