Brief Answer:
Polymorphic light reaction/urticaria
Detailed Answer:
Dear Friend
Welcome to XXXXXXX I am Dr Charu . I have read your query in detail. I understand your concern.
I saw both of the pics. It seems to be one of the following:
1) Polymorphic light reaction : as you have moved from a
cold place to a hot place , because of excess sun exposure, one tends to get extensively itchy
rash mainly on photoexposed areas.
From the pics, it is evident that your wife has rash mainly on upper back and upper chest , the photoexposed sites.
2) Urticaria: it is characterised by itchy wheals which are transient . The wheals usually disappears within 24 hours and reappear again. It also gets precipitated by weather change.
In such cases, i usually advice my patients to put a good sunscreen with SPF 50 + regularly at 9am, 12pm and 3 pm.
For itching and
redness, i advice antihistaminics like tab levocetrizine 5 mg night time and tablet
allegra morning.
Also sometimes consideration is given to put mild to moderate potency
topical steroid like
fluticasone or
mometasone over the lesions two times a day.
This is my best advice for you based on details available here. If you have any further query, you may please ask me. Else you may close the discussion and rate it.
Stay Healthy.