Annular Skin Lesions: Causes and Treatment

• Annular lesions are quite frequent, but they can also be confusing. The name "annular" is derived from the Latin word "annulus," which means "ringed." 

• Circular patches with an erythematous perimeter and center clearing characterize the lesions. 

• Dermatophytosis is the most prevalent cause of annular lesions in adults, and it can be properly identified without a biopsy. Other illnesses, however, may have a similar look. Other diseases must be ruled out, especially if the patient has previously failed dermatophytosis treatment.

Tinea Corporis

• Tinea corporis is a superficial fungal infection of the skin. It is sometimes known as ringworm, a misnomer derived from the annular look that was originally thought to be caused by invasive worms. Trichophyton, Microsporum, and Epidermophyton are the three most common causes.

• All dermatophytes can digest keratin, allowing them to enter the skin.

1. Treatment of Tinea Circinata

• There are several topical and systemic antifungal medicines available.

• It is recommended to begin with topical treatment (clotrimazole (Lotrimin), miconazole (Monistat), naftifine (Naftin), terbinafine (Lamisil), and butenafine (Mentax).

• In patients with the following conditions, systemic antifungal agents may be considered: 

• tinea corporis resistant to topical therapy

• disabling disease

• chronic infection

• primary or secondary immunosuppression

• Dermatophytosis of palms and soles. 

• Griseofulvin (Grisactin), terbinafine, and itraconazole (Sporanox) are effective systemic antifungal medicines. 

• Oral treatment for tinea corporis typically lasts two weeks

2.  Tinea Corporis Prevention

• Patients must also avoid reinfection by treating or avoiding contaminated soil, animals, and people.

Pityriasis Rosea

• Pityriasis rosea is a frequent, self-limiting papulosquamous rash that might seem similar to tinea corporis. It typically occurs between the second and fourth decades of life, with a high occurrence among adolescence, adolescents, and young adults.

• Women are more susceptible, although the exact percentage is unclear, and there is no ethnic bias. Pityriasis rosea appears to be more common in the spring.

• The herald patch is a single, ovoid macule that can range in size from 1 to 10 cm on the trunk. Except for the rash, most individuals are asymptomatic. 

• The rash is composed of tiny, fawn-colored, oval macules with peripheral, scaly collarettes comparable to the herald patch. 

• These lesions are often symmetrical and can occur anywhere on the body, but are most common in the neck and trunk.

• Because the lesions follow the cleavage lines of the skin, they have the appearance of a Christmas tree.

• Patients with severe pruritus may benefit from topical corticosteroids and oral antihistamines, but there is no effective remedy for pityriasis rosea.

Granuloma annulare

• Granuloma annulare is a frequent idiopathic, self-limiting cutaneous disease in adults and children. The disorder is benign and is distinguished by smooth and annular plaques and papules. 

• The lesions are most commonly observed on the hands, feet, wrists, and ankles, although they can occur elsewhere on the body. 

• Although most people have no symptoms, others may experience moderate pruritus.
• Granuloma annulare is more common in women, and the majority of individuals acquire it before the fourth decade of life.

• Granuloma annulare is classified as either localized, generalized, perforating, subcutaneous, or actinic.

• Localized granuloma annulare is the most frequent clinical type, accounting for around 75% of all cases.

• Most patients appear with one or more skin-colored to erythematous papules.

• The lesions are 1 to 5 cm in diameter and feature smooth, elevated borders. They can be solitary or form plaques. 

• The legs are the most typically afflicted place, with the palms, scalp, and plantar surfaces usually unaffected.

• Unlike tinea corporis, granuloma annulare lesions do not include scaling or accompanying vesicles or pustules.

• Within two years, around 50% of patients with localized granuloma annulare spontaneously resolve. 

• Patients with generalized granuloma annulare had more extensive involvement, with 10 or more lesions on average. 

• In these patients, spontaneous resolution is less prevalent than in those with isolated granuloma annulare, and remission in less than three to four years is improbable. 

• Perforating granuloma annulare lesions are tiny, umbilicated papules that mostly affect the hands and fingers. 

• Subcutaneous granuloma annulare is distinguished by big, skin-colored nodules that can extend into the dermis or subcutaneous fat.

• Granuloma annulare is thought to be caused by vasculitis, trauma, or hypersensitivity. Glucose tolerance problems are more likely in individuals with widespread granuloma annulare.

• Many treatment options are available, including intralesional corticosteroid injections, topical corticosteroids, electrodesiccation, cryotherapy, ultraviolet light therapy, dapsone, colchicine, or chloroquine. 

• Although these treatments have been demonstrated to relieve symptoms in some people, none has a clear benefit over others.

• Given the disease's unpredictability, determining the efficacy of any of these treatment choices is challenging.

Sarcoidosis

• Hutchinson originally identified sarcoidosis as an idiopathic, multisystemic granulomatous illness in 1877.

• Sarcoidosis is distinguished by the presence of noncaseating granulomas in nearly every organ system of the human body, most notably the lungs, skin, liver, spleen, eyes, salivary glands, and lymph nodes, particularly the mediastinal nodes. 

• Although it may occur at any age, young individuals between 20 to 40 are most at risk. 

• Clinical manifestations might range from asymptomatic to fulminant illness. 

• The usual skin alterations might include infiltrated papules and plaques, subcutaneous nodules, and scar infiltration. 

• The most prevalent lesions are papular lesions on the face, particularly in the periorbital area and the nasolabial folds, as well as lesions in the mucosal membranes. 

• They generally manifest as reddish-brown to purple lesions 1 to 3 cm in diameter. 

• In general, there is little epidermal alteration. The lesions may be big enough to merge, giving the appearance of annular lesions or plaques.

Hansen's Disease

• Mycobacterium leprae causes the illness, which is spread from person to person by droplets from the respiratory system. 

• The incubation period for this virus can range between three and twenty years M. Leprae develops best around 35.6°C (96.0°F), hence it prefers cooler regions of the body including skin, peripheral nerves, and eyes while avoiding the groin, axillae, and hairy scalp.

• The clinical manifestation varies greatly depending on the host's reaction to infection.

• Because of their robust cellular defenses, patients with tuberculoid leprosy typically appear with a few erythematous or violaceous, finely delineated macules or plaques.

• In those with dark skin, these lesions are hypopigmented. Scaling, baldness, and, most significantly, anesthesia may be linked with the lesions. 

• Nerve injury occurs when inflammatory cells assault bacteria-infiltrated nerves, resulting in sensory and motor dysfunction as well as palpable nerves. 

• Patients with lepromatous leprosy, on the other hand, have poor cellular immunity and exhibit widespread, bilaterally symmetric macules and papules that may merge or become nodular. 

Urticaria

• Urticaria is distinguished by pruritic, well-circumscribed erythematous skin lesions (wheals) with erythematous elevated borders and pale cores. 

• Urticaria may afflict 10 to 20% of the population,20 although this figure may be underestimated due to the self-limited character of this eruption, which may encourage many patients to avoid seeking medical assistance. 

Subacute cutaneous lupus erythematosus

• Subacute cutaneous lupus erythematosus might manifest as an annular lesion. It is characterized by photosensitivity, and the lesions are often limited to exposed areas. 

• Systemic illness is mild to moderate, and renal disease is uncommon.

References

https://www.aafp.org/pubs/afp/issues/2001/0715/p289.html#afp20010715p289-b19