How to Find the Cause of Itchy Skin without Rash
Diagnosing the Origin of Generalized Itching without Visible Rashes
Aug 24, 2009
While diagnosis of generalized itchy skin with visible skin rashes is usually made through proper clinical examinations, the whole scenario changes when the pruritus is present without any evident skin rash. It is easy to be fooled by the non specific skin rashes caused by scratching, rubbing or contact sensitivities to topical applications.
The following is a general outline on how to diagnose the cause of generalized itching without visible skin rashes:
How to Find the Cause of Itchy Skin without Rash: Careful History Taking.
- How long has the itching been there? Where did it start? Is it generalized or limited to certain parts of the body? When is the itching more? Does it keep the patient awake? Itching in scabies is limited to certain parts of the body and is more severe during night.
- Is the itching continuous or sporadic?
- Has the patient noticed any spikes in the intensity of pruritus after any activity, food or drug intake? Any relation to emotional upheavals?
- Anyone else in the house has similar itching? An affirmative answer points more towards infestations like scabies or other insects such as bed bugs.
- Any history of unprotected sex, weight loss, fever, drug intake etc?
How to Find the Cause of Itchy Skin without Rash: Meticulous Skin Examination
- The entire skin should be examined under bright examination lights. Subtle skin changes and rashes may be missed otherwise. The major skin diseases causing itchy skin should be actively sought for. The typical sites of involvement of scabies burrows(finger webs, wrist, medial aspect of elbows, under breasts and on the genitals in males), itchy bumps on the elbows and scalp in dermatitis herpetiformis, dry skin, minute grouped tell tale bumps of bug bite etc will point towards the respective skin diseases.
- Scratch the skin and watch for the appearance of wheals: Indicative of dermographism in urticaria. Rubbing produces itching and wheals in mastocytosis as well, called the Darier’s sign.
- Application of normal temperature water causes itching in aquagenic pruritus and whealing in aquagenic urticaria; cold water causes itching and wheals in cold urticaria.
- Note the state of oral and genital mucosa, hair and nails.
How to Find the Cause of Itchy Skin without Rash: General Physical and Systemic Examination
- General health, anemia, jaundice, liver and spleen, respiratory, circulatory and digestive systems’ review.
- Examination of all lymph nodes; rectal and pelvic examinations.
How to Find the Cause of Itchy Skin without Rash: Laboratory Investigations
- Laboratory tests are indicated in pruritus either to confirm the suspicions from the history taking and clinical examinations or if no clue was forthcoming from them.
- Complete blood work up: CBC, ESR, blood sugar, liver and kidney function tests, thyroid tests, hepatitis profiles, serological tests for parasites. Peripheral smear should be sent for opinion on the morphology of the blood cells. If suspicious, a bone marrow examination may be requested.
- Stool and urine examinations.
- X ray chest and bone scans
- In males above middle age, prostate specific antigen, and, in females, PAP smear is mandatory to rule out prostate and cervical cancers respectively.
Referral to hematological and other relevant departments is called for if no definite diagnosis could be made even after these investigations and the patient’s intense itching continues unabated. Pin pointing the exact causes of the generalized itching without skin rash is thus essential for the proper treatment of the itchy skin disease.
Reference
- Pruritus, in Rook’s Textbook of Dermatology, 7th Edition, 2004
- Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology, Fifth Ed, 2005
Disclaimer
The information given in this article is for educational purpose only so that patients are aware of the options available. No diagnosis should be made or treatment undertaken without first consulting your doctor. If you do so, the author or suite101 will not be responsible for any consequences. The images provided are for illustration purpose only.
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