Eczema

Scenarios: Itchy, skin rash.

Questions to ask:

• When did you first notice the rash, where did it start, how has it changed since then, does it come and go, does it seem worse at particular times of year, is it worse before your period or in pregnancy?
• Have you ever had anything like it in the past, any hayfever, asthma, skin allergies when you were younger?
• Does anyone in the family have any of those problems?
• Is there anything else you see a doctor for? Any previous operations?
• Are you taking any medications at the moment? Any allergies?
• Any other medical problems run in the family?
• What do you do for a living – does that involve any chemicals or anything that you think may be irritating your skin?
• Who’s at home with you, any pets?
• Any change in bath products or washing liquids or anything like that recently?
• Do you smoke, ever smoked, drink alcohol or take recreational drugs?
• How has your mood been recently?
• Do you have any particular worries or questions for me today?

Systems to examine:

• Cutaneous: Look for the different possible types – atopic (often flexural location), erythrodermic, contact/irritant, pompholyx, discoid, varicose; and then look for key features such as erythema and lichenification, fissuring, excoriations, generally dry skin, and any evidence if possible infection (eg: weeping and crusting of staph aureus, vesicles and erosions of herpeticum, with the latter being an indication for admission).

Differentials to exclude:

• Irritant contact dermatitis: Beneath watch straps, under earrings or contact points of belts or jewellery,  on specific finger tips (eg: chefs and garlic).
• Psoriasis: Particularly the flexural form of psoriasis, look for suggestive nail changes or involvement in other areas such natal cleft or umbilicus or hairline.
• Discoid lupus: Erythematous scaly patches, mostly in sun exposed areas, which heal with pigmentation, scaring and alopecia.
• Infective: Intertrigo (candidiasis within a skin fold), tinea (dermatophyte fungal infections that usually are erythematous with minimal overlying scale and an annular raised edge), and scabies (look interdigitally, very itchy, excoriations).

Investigations:

• Bedside tests: MCS and viral swabs (exclude superadded infection).
• Special tests: Biopsy (spongiosis, keratosis, inflammatory infiltrate).

Management:

• Non-pharmacological: Educate, supplementary written information, support groups, involvement from General Practitioner and dermatologist as required, avoid precipitants and allergens if appropriate, avoid irritants in clothing such as synthetic materials and woollen clothes.
• Medical: Topical – emollients (apply often and liberally, especially if features of a flare starting with increased irritability, dryness, redness and swelling), with wrapping to improve absorption, steroids, tacrolimus; phototherapy; or oral therapy like prednisolone or steroid sparing agents like cyclosporin, antibiotics and anti-virals if infected.

Questions:

1. What is the difference between skin prick testing and patch testing? Skin patch tests are typically used to detect contact allergens which are causing an irritant dermatitis, whilst skin prick test are used to identify other allergens including inhaled ones that may be contributing to asthma or hayfever symptoms.