Simple cases
Case 19
20-year-old man complains of very dry skin
History
How long has your skin been so dry and scaly?
I remember having problems in grade school with dry, sensitive skin.
This is a good place to start.
Do you have asthma, hay fever or eczema, or did you ever have them?
Yes, as a child I had eczema in my elbow folds and behind my knees.
About 30% of patients with this disorder also have atopic dermatitis.
Do you take any medications?
No.
Good question, as retinoids and lipid-lowering agents can cause a similar clinical picture.
Do the skin changes vary much with seasons and climate?
Yes, I am lot better off in summer.
Good question. Many patients with this disease do better when it is warm and moist, and flare at the start of the heating period in the late fall.
Do you have any problems with vision, hearing or taste?
No.
Good question, as all three of these senses can be affected in some rare scaly disorders. For example, in Refsum, syndrome, an autosomal recessive inherited genodermatosis, there is a derangement in phytanic acid metabolism and patients often have problems seeing and hearing.
Does anyone else in your family have similar skin problems?
I'm not sure. My father has dry skin on his shins, but he is nowhere near as bad off as I am.
Good question; this disease does have a genetic background, but not all affected patients are equally effected (variable expressivity). In addition, environmental factors influence the severity of the disease.
Lesion
Choose the right efflorescences:
False. A crust contains dried serum, pus or blood.
Lichenification is the result of persistent skin rubbing and featured exaggerated skin markings.
Poikiloderma features telangiectases, atrophy and pigmentary changes. All are missing here.
Correct. This is a scaly disease.
Diagnosis
Choose the right diagnosis:
False. Vitiligo shows sharply circumscribed areas of total depigmentation and never has scales.
Correct. The history of atopy, the sparing of the flexural folds, and the history of similar disease in the father suggest this young man probably has ichthyosis vulgaris, transmitted in an autosomal dominant fashion.
False. Widespread tinea corporis also has scales, but is more localized with scaly annular erythematous lesions.
False. Psoriasis shows silvery scales on an erythematous base, rather than diffuse, non-inflamed scales.
Therapy
Choose the right therapy(ies):
Good choice. Urea has a keratolytic effect and helps retain water.
False. The topical vitamin D products are used in psoriasis.
Salicylic acid is a good keratolytic. When it is applied to wide areas, there is enough absorption to produce salicylism. It should be used with great care in children.
Propylene glycol is an effective, easily applied keratolytic without measurable toxicity.
