Types of Skin Rashes and Diagnosis
A skin rash is an inflammation of the skin causing discoloration and distortion of the normal skin. These may be in the form of blisters, scaling, skin ulcers, bumps on the skin and change in colour of the skin The rashes are a sign of some underlying disease and maybe Infective or non-infective.
Some of the non-infective skin rashes are
Atopic dermatitis, which is also called eczema. This is more common in children and is associated with allergic reactions. The person may have associated hay fever and asthma
Seborrheic dermatitis– This is a red scaly rash common amongst the adults and is normally in the scalp and the head area
Contact dermatitis-This is a rash that occurs when the skin comes in contact with some chemicals that can cause irritation to the skin.E examples of this are poison ivy, poison oak etc. Sometimes the contact dermatitis can occur on contact with some jewelry or some cosmetics also
Diaper rash is also a kind of contact dermatitis when the feces or urine in the diaper is in prolonged contact with the skin. This happens when the diaper is not regularly changed
Stasis dermatitis occurs in the lower legs in people who have to swell in the legs or have varicose veins. This occurs due to poor circulation in the veins
Psoriasis– is a bumpy scaly lesion occurring in the on the scalp, elbows, and knees. The lesion is scaly and the scales are silvery.
Hives– these are red itchy bumps and come suddenly the whole body and normally resolve within 8-10 hours
Nummular eczema is coined shaped plaques on the skin and is associated with dry skin
Drug eruptions– are a reaction to certain drugs.
Heat rash occurs due to occlusion of the sweat glands during hot and humid weather.
Some of the infective rashes are caused by
Rashes due to parasites
Diagnosis of the cause of the rashes in the laboratory
Complete Blood Count – The total count will be increased in the case of bacterial rashes. In the case of viral rashes, there will be a relative increase in the lymphocytes and in other kinds of allergic rashes the eosinophil’s will be increased
Absolute eosinophil count – these are increased if the rash is allergic in nature
IgE Levels – These levels are increased in case of allergic rashes
KOH preparation for Fungus– the scrapping of the rash is taken and observed under the microscope for fungi
Swab for culture – A swab is taken from the skin and put up for culture and this is useful if the rash is due to bacterial infection
Skin Biopsy – A skin biopsy may be taken if the rash is chronic. The biopsy is then submitted for histopathological examination to reach a diagnosis