Graft-Versus-Host Disease (GVHD) is a serious complication that can occur after an allogeneic stem cell or bone marrow transplant. This condition develops when the newly transplanted immune cells from the donor recognize the recipient’s tissues as foreign. These donor cells then mount an immune attack against the patient’s own body, leading to various symptoms. When this immune reaction specifically targets the largest organ of the body, it is known as skin GVHD.
Understanding Skin Graft-Versus-Host Disease
Skin GVHD is an immunological reaction where donor immune cells, specifically T cells, perceive the recipient’s skin cells as foreign and attack them. This occurs because, except for identical twins, everyone possesses unique human leukocyte antigens (HLAs) on their cells, which act like identification tags. Donor cells, lacking these specific HLA markers, identify the host’s skin cells as foreign. This immune response leads to inflammation and damage within the skin.
Identifying Skin Symptoms
Skin GVHD presents with observable changes and sensations. Patients experience a rash, which may appear as maculopapular (flat, red spots with small bumps) or erythematous (reddened) areas. This rash can resemble a sunburn and may be accompanied by intense itching or a burning sensation. The affected skin might also feel dry and tight. In more severe cases, blistering and peeling of the skin can occur. Over time, the skin may show changes in texture, becoming thickened, bumpy, or hardened, and can also exhibit alterations in color, appearing darker, lighter, or even purplish.
Distinguishing Acute and Chronic Skin GVHD
Skin GVHD is categorized into acute and chronic forms, each with distinct characteristics. Acute skin GVHD develops within the first 100 days following a transplant, though it can appear later. This form begins with an itchy, painful red rash, appearing on the palms of the hands, soles of the feet, ears, face, neck, and shoulders. In severe instances, the rash can spread across a larger body surface area and may progress to blistering or peeling, similar to a severe sunburn.
Chronic skin GVHD manifests after 100 days post-transplant, though its onset can vary. This form presents with a broader range of symptoms, mimicking autoimmune conditions like scleroderma. The skin may become hardened, thickened, and tight, leading to a “woody” sensation or a pulling feeling underneath the skin. This hardening, known as sclerosis, can restrict joint movement, particularly in areas like wrists, elbows, shoulders, and ankles. Signs include persistent dryness, loss of skin elasticity, changes in pigmentation (red, pink, purple, brown, or white discoloration), hair loss (including graying hair), and nail abnormalities such as ridging, brittleness, or even loss of nails.
Diagnosis and Management
Diagnosing skin GVHD involves a clinical examination by a transplant physician or dermatologist. To confirm the diagnosis and distinguish it from other skin conditions, a skin biopsy is performed. During this procedure, a small tissue sample from the affected skin is removed under local anesthetic and examined under a microscope by a pathologist for specific cellular changes characteristic of GVHD.
The management of skin GVHD aims to reduce inflammation, suppress the immune response, and alleviate symptoms. For mild cases, topical treatments are used. These include steroid creams, such as triamcinolone or clobetasol, applied directly to the affected skin, and emollients to combat dryness and itching. For more widespread or severe skin GVHD, systemic medications are necessary. Oral corticosteroids, like prednisone or methylprednisolone, are prescribed to suppress the overactive immune response.
If corticosteroids are ineffective or to reduce reliance on them, other immunosuppressive drugs may be utilized. These include calcineurin inhibitors like cyclosporine or tacrolimus, mTOR inhibitors such as sirolimus, or JAK inhibitors like ruxolitinib. Light therapies like extracorporeal photopheresis (ECP) or psoralen plus ultraviolet A (PUVA) may also be used. Supportive care measures, such as antihistamines for itching and diligent skin protection, are part of the overall management plan. Treatment is individualized and requires ongoing medical supervision.