Actinic Prurigo - Symptomatic Complications and Effective Management

Introduction

Actinic prurigo is also called hydro as aestival or prurigo or Hutchinson summer. The primary etiology of actinic prurigo is sun exposure. Actinic prurigo is a dermal condition characterized by papules, nodules, and intense pruritus. It is observed that prepubescent females are more susceptible to actinic purpura. The summer season favors the incidence of actinic prurigo, and the condition persists till winter. The primary cause of actinic prurigo is sun exposure and ultraviolet or UV rays. It is also found that actinic prurigo has a robust genetic etiology.

What Is Actinic Prurigo?

Actinic prurigo is a dermal condition characterized by a papulonodular lesion with intense pruritus due to sun exposure. Sun exposure is not the exclusive cause of actinic purpura, and it is observed that actinic prurigo also occurs with a strong genetic background. Sun-exposed areas are typically affected with actinic prurigo, which includes the face, hands, neck, and upper extremities. Non-sun-exposed areas of the body, such as the buttocks region, are also observed with the symptoms of actinic prurigo in rare cases. Actinic prurigo can occur in any age group and has no gender preference. Prepubertal females are highly susceptible to actinic prurigo. Limiting or avoiding sun exposure helps prevent actinic prurigo and its complications. Actinic prurigo is more prevalent among American Indians, South America, and Central America.

What Causes Actinic Prurigo?

Actinic prurigo is primarily caused by sun exposure and has a strong genetic etiology. Actinic prurigo is an autoimmune condition, and the human leukocyte antigen or HLA DR4 allele variant is observed in most people affected with actinic prurigo. Apart from sun exposure and genetic causes, certain triggers are found to contribute to the occurrence of actinic prurigo.

Some contributing factors to the incidence of actinic prurigo are mentioned below.

• Sun exposure.

• Genetic predisposition.

• Environmental exposure.

• Ultraviolet rays (UV) effects.

• High altitude.

What Are the Symptoms of Actinic Prurigo?

Actinic prurigo is a dermal disorder caused primarily by sun exposure and other causes. The symptoms of actinic prurigo are mostly present in the sun-exposed areas of the body. The most common areas of actinic prurigo are the face, zygomatic arches, nose, nasal bridge, lower lip, conjunctiva, neck, trunk, and upper extremities. Lips are involved in the majority of patients. Sometimes the symptoms of actinic prurigo are also seen in non-sun-exposed areas such as the buttocks. Intense pruritus, itching sensation, excoriations, thick skin, scarring, and pigmentation are the symptoms of actinic prurigo. The symptoms of actinic prurigo are seen within an hour of sun exposure. Hypopigmentation or hyperpigmentation can occur. The hallmark sign of actinic prurigo is the angular cheilitis, called the inflammation on the corner of the lips.

The other symptoms of actinic prurigo are listed below.

• Pruritus.

• Irritation.

• Papules.

• Nodules.

• Chronic scratching.

• Crusting and scaling.

• Itching sensation.

• Excoriations.

• Thick skin.

• Scarring.

• Hypopigmentation.

• Hyperpigmentation.

• Angular cheilitis.

• Conjunctivitis.

What Is the Diagnosis of Actinic Prurigo?

The diagnosis is based on the history of sun exposure and physical examination. Environmental exposure is also evaluated with history. The summer climate favors the occurrence of actinic prurigo, and the symptoms of actinic prurigo will persist till winter. The physical examination must include the papulonodular lesions in the sun-exposed areas and the non-sun-exposed areas in rare cases. The other diagnostic aids of actinic prurigo include skin photo testing, histological findings, and genetic screening tests. The genetic evaluation must include screening human leukocyte antigen or HLA DR4 allele variant. In addition, various other laboratory tests and immunofluorescence are done to diagnose the photodermatosis condition.

The diagnostic tool for actinic prurigo is described below.

• Proper history.

• Physical examination.

The histopathological finding of actinic prurigo is listed below.

• Hyperkeratosis.

• Spongiosis.

• Acanthosis in the epidermis.

• Lymphocytic infiltration.

• Perivascular infiltration.

• Lip biopsy.

• Genetic screening.

• Immunofluorescence.

What Is the Differential Diagnosis of Actinic Prurigo?

Actinic pruritus is a photodermatosis condition and is a hereditary type of polymorphous light eruption or PMLE. The symptoms are similar to other dermal conditions. Therefore, the comparison of symptoms will help in differential diagnosis and may help to avoid misdiagnosis. Some of the differential diagnoses of actinic purpura are listed below.

• Polymorphous light reaction or PMLE.

• Systemic lupus erythematosus or SLE.

• Porphyria.

• Atopic dermatitis.

• Hydroa vacciniforme.

• Chronic actinic dermatitis.

What Is the Treatment of Actinic Prurigo?

Sun exposure should be reduced or avoided to prevent or reduce the risk of actinic prurigo. A mild form of actinic prurigo will be resolved by reducing sun exposure. The proper preventive measure is followed to reduce or avoid sun exposure and ultraviolet or UV rays. In severe cases, phototherapy is advised. Psoralen and ultraviolet light A can be used. Topical corticosteroids are used to relieve the itching sensation. Other chemotherapy includes sedating antihistamines, antimalarials, tetracyclines, and systemic corticosteroids. Hallmark therapy for actinic prurigo is Thalidomide. Neuropathy and teratogenicity are the minor side effects of Thalidomide.

The other treatment for actinic prurigo is described below.

• Sun protective measures include sunglasses, a broad hat, and sunscreen containing sun protection factors or SPF.

• Wearing clothing with long sleeve pants will reduce sun exposure.

• Topical corticosteroids for relieving itching.

• Antimalarials to improve inflammatory changes, such as hydroxychloroquine.

• Antihistamines.

• Tetracyclines.

• Systemic corticosteroids.

• Thalidomide.

• Immunosuppressive drugs such as cyclosporine A.

• Photochemotherapy includes psoralen and ultraviolet A or PUVA.

What Are the Complications of Actinic Prurigo?

The complications of actinic prurigo occur in its severe form. Some side effects of chemotherapy are also observed in some patients, including peripheral neuropathy and teratogenicity. Thalidomide medication is contraindicated during pregnancy and for females trying to become pregnant.

The complications of actinic prurigo are given below.

• Secondary bacterial infections.

• Impetigo is called the red sores on the face.

• Contact dermatitis.

• Scarring.

Conclusion

Actinic prurigo is a rare dermal disorder due to chronic sun exposure affecting prepubescent females more than males. Actinic prurigo has no gender predilection. Actinic prurigo is characterized by intense pruritus, papules, and nodules on the sun-exposed areas such as hands, face, neck, and upper extremities, and sometimes in non-sun-exposed areas. A mild form of actinic prurigo will be resolved by following sun-protective measures. Topical and systemic corticosteroids are advised for symptomatic relief. Thalidomide is the hallmark therapy for actinic prurigo. Prevention or avoiding sun exposure will reduce or prevent the risk of actinic prurigo.