Difference Between Hives and Scabies

Key Difference – Hives vs Scabies
 

The sudden appearance of erythematous and edematous bump like lesions on the skin is known as hives or urticaria. Scabies is a disease with dermatological manifestations that is caused by a mite named Sarcoptes scabiei. Although scabies is of an infectious origin, hives are usually due to the allergic or hypersensitivity reactions that are triggered by the exposure to an allergen. This is the key difference between hives and scabies.

CONTENTS

1. Overview and Key Difference
2. What are Hives
3. What is Scabies
4. Similarity Between Hives and Scabies
5. Side by Side Comparison – Hives vs Scabies in Tabular Form
6. Summary

What are Hives?

The sudden appearance of erythematous and edematous bump like lesions on the skin is known as hives or urticaria.

These lesions can appear anywhere on the skin and can give rise to pruritus or a burning sensation. The size of hives varies but in some occasions they can merge together to form larger lesions called plaques. Usually, the occurrence of hives is a self-limiting condition where individual lesions disappear within a day. Despite the disappearance of already existing lesions new ones continue to appear depending on the underlying etiology.

Causes

The release of histamine plays a key role in the pathogenesis of urticarial rashes.

• Allergic and hypersensitivity reactions
• Adverse effects of various drugs such as NSAIDS and ACE inhibitors

The variety of hives lasting for less than six weeks is called acute hives. If it lasts for more than six weeks, it is identified as chronic hives.

Main Types of Urticaria

There is a variant of urticaria called the angioedema that predominantly affects the subcutaneous tissues. Therefore, the erythema and the concomitant edema are less pronounced.

Investigations

A good clinical history is usually sufficient to identify the underlying disease. But in case of an abnormal presentation, following tests can be performed.

• ESR
• CRP
• RAST
• Chest X-ray

Treatment

The management of urticaria varies according to the etiology. The common measures and procedures followed in treating this condition includes

• Avoiding the exposure to allergens and environmental conditions that trigger urticaria
• Use of antihistamines
• Wearing protective clothing

What is Scabies?

Scabies is caused by a mite named Sarcoptes scabiei. The fertilized female mites burrow through the stratum corneum of the skin and start laying eggs. These eggs produce sexually mature mites within 2-3 weeks.

Presentation

Initially, within the first few weeks, the patient remains symptomless. Thereafter, the pruritus dominates the clinical picture, and this usually worsens at night. Most of the burrows are seen on the sides of fingers and toes and also on the flexural aspects of the wrists. Scabies affects face only during the infancy. Burrows in the genital regions are typically associated with erythematous rubbery nodules.

Complications

• Superimposed bacterial infection with the appearance of pustules. In rare cases, the patient can also get glomerulonephritis.
• Repeated exposure to scabicides results in adverse effects such as skin irritation and eczema.
• The erythematous lesions can persist in the genital region for several months even after the proper treatments. Venereal diseases contacted during this period can be masked and ignored because of their effect.
• Norwegian scabies (also called the crusted scabies because of the eruption of characteristic crusted lesions) is a severe form of scabies that occurs in immunocompromised individuals.

Investigations

• Microscopic examination of the acarus
• Microscopic examination of the skin scrapings mounted in potassium hydroxide to identify mites and eggs.
• Dermatoscopy

Treatment

• Use of scabicides such as malathion
• Topical treatment together with the oral administration of ivermectin can be effective in the management of Norwegian scabies.
• Permethrin cream is usually used in the treatment of scabies in pediatric patients.
• All the family members and the sexual contacts of the patient should be treated regardless of the presence of symptoms.

 What is the Similarity Between Hives and Scabies?

• Both conditions have dermatological manifestations.

What is the Difference Between Hives and Scabies?

Hives vs Scabies
The sudden appearance of erythematous and edematous bump like lesions on the skin is known as hives or urticaria.	Scabies is a disease with dermatological manifestations that is caused by a mite named Sarcoptes scabiei.
Thyroid Levels
This is predominantly due to the exposure to allergens.	This is due to the Sarcoptes scabiei infestation.
Histamine
Histamine plays a key role.	Histamine is not involved in the pathogenesis.

Summary – Hives vs Scabies

The sudden appearance of erythematous and edematous bump like lesions on the skin is known as hives or urticaria. Scabies is a disease with dermatological manifestations that is caused by a mite named Sarcoptes scabiei. Hives usually is a result of an allergic reaction triggered by the exposure to some allergic agent whereas scabies is due to the Sarcoptes scabiei infestation. This is the difference between hives and scabies.

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References:

1. “Urticaria” By BruceBlaus – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Scabies-burrow” By Michael Geary – Own work (Public Domain) via Commons Wikimedia

Image Courtesy:

1. “Urticaria” By BruceBlaus – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Scabies-burrow” By Michael Geary – Own work (Public Domain) via Commons Wikimedia