Annular Lesions

Comparison of Annular Lesions

Diagnosis	Clinical presentation	Treatment options
Tinea corporis	Scaly, annular, erythematous plaques or papules on glabrous skin	Topical and systemic antifungals
Discoid Eczema	Less likely to have central clearing (but can occur) More confluent scales
Annular psoriasis	Silvery scale Nail pitting Family history of psoriasis
Pityriasis rosea	Small, fawn-colored, oval patches with fine scale along the borders, following skin cleavage lines	Topical and systemic corticosteroids; UVA, UVB
Granuloma annulare	Indurated, nonscaly, skin-colored annular plaques and papules, usually on the extremities	Topical and intralesional corticosteroids
Sarcoidosis	Indurated, erythematous plaques	Topical, intralesional and systemic corticosteroids; antimalarials; thalidomide
Hansen’s disease	Erythematous annular plaques, with or without scale	Dapsone; rifampin (Rifadin)
Urticaria	Evanescent annular, nonscaly, erythematous plaques	Oral antihistamines
Subacute cutaneous lupus erythematosus	Annular or papulosquamous plaques, with or without scale, on sun-exposed areas	Topical, intralesional and systemic corticosteroids; antimalarials
Erythema annulare centrifugum	Annular patches with trailing scale inside erythematous borders	Topical and systemic corticosteroids; oral antihistamines; treatment of the underlying cause

Tinea Corporis (Ringworm)

Definition and Causes:

• Chronic fungal infection of skin, excluding hands, feet, scalp, face, or groin.
• Caused by Trichophyton, Microsporum, and Epidermophyton, commonly Trichophyton rubrum, Trichophyton tonsurans, and Microsporum canis.
• Dermatophytes assimilate keratin, infecting the stratum corneum.

Transmission

• Spread through contact with infected persons, animals, or soil.
• Autoinoculation from infected nails, scalp, or feet is possible.
• More common after puberty, no sexual predilection

Risk factors

Medical risk factors include:

• Previous or concurrent tinea infection
• Diabetes mellitus
• Immunodeficiency
• Hyperhidrosis
• Xerosis
• Ichthyosis.

Environmental risk factors include:

• Household crowding
• Infection of household members
• Keeping house pets
• Wearing occlusive clothing
• Recreational activities involving close contact with others including shared change rooms.

A genetic predisposition has been postulated, particularly for tinea imbricata.

Clinical Presentation:

• Well-demarcated, erythematous papules or plaques.
• Gradual enlargement of lesions with active, raised, or scaly borders.

Diagnosis:

• KOH microscopic slide preparation from scales at the lesion’s active border.
• Examination under low-power magnification reveals septate hyphae.
• Fungal cultures recommended if KOH preparations are negative.

General Measures

• Hygiene: Skin should be kept clean and dried thoroughly.
• Clothing: Wear loose-fitting, light clothing in hot, humid climates.
• Prevention: Avoid close contact with infected individuals and sharing personal items like towels.
• Household Examination: Check household members and pets for infections to reduce re-infection risk.

Specific Measures

Topical Antifungals

• Medications: Imidazoles (e.g., clotrimazole, ketoconazole) and terbinafine.
• Application: Cover the lesion adequately, extending beyond its margins.
• Duration: Continue treatment for 1–2 weeks after the rash has visibly cleared to prevent recurrence.

Oral Antifungals

• Indications:
  • Involvement of hair-bearing areas.
  • Extensive infection.
  • Failure of topical treatment.
  • Conditions like Majocchi granuloma and tinea imbricate.
• Agents: Terbinafine and itraconazole are commonly recommended.

Outcome

• Resolution: Tinea corporis is curable with appropriate treatment and good compliance.
• Recurrence: Can occur if treatment is stopped prematurely or if the infection source isn’t adequately treated.

Discoid Eczema

• Also known as nummular dermatitis.
• Characterized by scattered, coin-shaped, well-defined plaques of eczema.

Causes

• Unknown: Specific cause of discoid eczema is not well-understood.
• Associated Factors:
  • Local injuries (scratch, insect bite, burns).
  • Skin infections like impetigo.
  • Contact dermatitis.
  • Dry skin.
  • Varicose veins.

Who Gets Discoid Eczema?

• Affects all age groups, slightly more common in older adult males and younger adult females.
• Associated with chronic alcoholism in males.
• Drug-induced due to medications causing skin dryness.

Clinical Features

• Forms:
  • Exudative (acute): Oozy papules, blisters, and plaques.
  • Dry (subacute or chronic): Erythematous dry plaques.
• Mostly affects limbs, particularly legs; may be widespread.
• Itchy and inflamed plaques, usually 1–3 cm in diameter.

Diagnosis

• Appearance: Characteristic and quite distinctive.
• Tests:
  • Bacterial swabs to detect Staphylococcus aureus.
  • Scrapings for mycology to rule out tinea corporis.
  • Patch testing for contact allergies, especially to metals like nickel and chromate.

Differential Diagnosis : Resembles tinea corporis, plaque psoriasis, and pityriasis rosea.

Treatment

Non-Pharmacological

• Skin Protection: Avoid minor injuries and irritants.
• Emollients: Frequent application to relieve itching and dryness. Useful types include glycerine, cetomacrogol cream, and urea cream.
• Avoiding Allergens: Important if patch testing reveals specific allergies.

• Topical Steroids: Reduce inflammation and clear dermatitis. Applied directly to patches.
• Antibiotics: Used if dermatitis is blistered or infected.
• Oral Antihistamines: May reduce itching.
• UV Treatment: Phototherapy for widespread cases.
• Steroid Injections: For stubborn areas.
• Oral Steroids: Reserved for severe and extensive cases.
• Other Oral Treatments: Methotrexate, azathioprine, or ciclosporin for persistent cases, monitored by a dermatologist.

Outcome

• Chronic condition with potential for relapse, especially in colder months.
• Many cases eventually resolve over time.

Pityriasis Rosea:

• Self-limited papulosquamous eruption, possibly viral.
• Presents with “herald patch” followed by fawn-colored, oval patches.
• Treated with corticosteroids, antihistamines, or UV light; spontaneous resolution in 6-8 weeks.

Granuloma Annulare:

• Idiopathic condition with skin-colored annular plaques and papules.
• Commonly on hands, feet, wrists, ankles.
• Treatment often not necessary; options include corticosteroids and UV light therapy.

Sarcoidosis:

• Multisystemic granulomatous disease.
• Noncaseating granulomas in various organs.
• Skin lesions: infiltrated papules, plaques, nodules.
• Treated with systemic corticosteroids or alternative immunosuppressive agents.

Hansen’s Disease (Leprosy):

• Caused by Mycobacterium leprae.
• Affects cooler body parts: skin, nerves, eyes.
• Tuberculoid leprosy presents with erythematous macules/plaques, anesthesia.
• Lepromatous leprosy presents with symmetric macules, papules, nodules.
• Treated with dapsone and rifampin.

Urticaria:

• Pruritic, erythematous skin lesions with central clearing.
• Classified as allergic, physical, or idiopathic.
• Treated with antihistamines; individual lesions last 90 minutes to 24 hours.

Subacute Cutaneous Lupus Erythematosus (SCLE):

• Annular or papulosquamous plaques on sun-exposed areas.
• Associated with SSA/Ro antibodies and mild to moderate systemic disease.
• Treatment includes corticosteroids and antimalarials.

Erythema Annulare Centrifugum:

• Annular patches with trailing scale inside borders.
• Possibly a hypersensitivity reaction to various conditions.
• Treatment generally not required; symptomatic improvement with corticosteroids or antihistamines.

Erythema marginatum (annular erythema)

• secondary to rheumatic fever, Reaction to group A streptococcus bacterial infection.
• Typical Precursors: Streptococcal pharyngitis and, in some cases, skin infections.
• Recurrence: Higher risk after initial episode.

Demographics:

• Age Group: Commonly affects children aged 5–15 years.
• Geographical Prevalence: Predominant in developing countries; rare in developed countries except among Maori and Pacific people in New Zealand, Aboriginal Australians, and Pacific Islanders.
• Associated Factors: Poverty, overcrowding, poor sanitation, and possible genetic susceptibility.

Clinical Features:

• Non-specific Symptoms: Fever, abdominal pain, muscle aches.
• Specific Symptoms:
  • Polyarthritis (multiple inflamed joints).
  • Carditis (heart inflammation).
  • Sydenham chorea (nervous system disorder).
• Skin Signs:
  • Erythema marginatum (annular erythema).
  • Subcutaneous nodules.

Complications:

• Rheumatic Heart Disease: Permanent damage to heart valves and muscle, causing heart failure, pericarditis, and irregular heart rhythms.

Diagnosis:

• Method: Jones criteria, requiring evidence of prior streptococcal infection.
• Tests: Blood tests for antibodies (antistreptolysin O, antideoxyribonuclease B), throat swab cultures, ESR/CRP levels, electrocardiogram, echocardiogram.

Treatment:

• Initial Treatment: Oral penicillin for streptococcal infection.
• Long-term Prevention: Continuous penicillin to prevent further infections.
• Anti-inflammatory Treatment: Aspirin, naproxen, or corticosteroids for severe cases.
• Surgical Intervention: Possible in cases with severe rheumatic heart disease.

Prevention:

• Early Treatment: Timely management of group A streptococcal pharyngitis.
• Vaccination: Under development.

Other Annular Lesions:

• Erythema chronicum migrans (Lyme disease), erythema multiforme, and psoriasis can also present with annular lesions.