Actinic reticuloid L57.1

Chronic dermatitis in light-exposed areas of the skin with extremely low erythema threshold (UVA and UVB), which occurs mainly in older men; this very specific chronic dermatitis is considered a particularly severe subtype of chronic actinic dermatitis.

Photosensitivity is the key feature of this chronic photodermatosis, with the spectrum of action including UVB, UVA and visible light above 400 nm.

There are usually extensive, severely itchy, painful, chronic eczematous skin changes with considerable lichenification and clear infiltration of the skin, which leads to a leathery increase in the consistency of the lesional skin. The skin changes are clearly demarcated from the unexposed skin, whereby this transition is not sharp in a linear fashion, but rather irregularly loosened with "scattered phenomena". Ectropion (clinically very disabling) often occurs with eyelid involvement and requires constant ophthalmologic treatment.

The skin changes persist for months after low UV exposure, can subside in winter and then exacerbate and persist again in spring after brief UV exposure. After a number of years, this rhythm is lost and the eczematous skin changes persist all year round, with an additional worsening of the chronic eczema condition occurring in the light-rich season.

Facies leontina as the maximum manifestation of the actinic reticuloid in the facial area is possible.

Furthermore, in rare cases of severe light sensitization, the eczematous process can also affect the entire integument with the development of erythroderma.

In very rare cases, a transition to malignant lymphoma of the T-cell type has been reported.

Remark: For further illustrations see below. Chronic actinic dermatitis.

Acanthosis, papillomatosis, band-shaped, dense subepidermal, epitheliotropic lymphohistiocytic infiltrate. Only slight spongiosis. Pautrier microabscesses may occur. A certain nuclear polymorphism of the lymphocytes is detectable, which makes it difficult to differentiate from an initial T-cell lymphoma.

Immunohistochemical analysis of the skin infiltrate confirms the presence of activated T cells, numerous histiocytes, macrophages and B cells (Paek SY et al. 2014).

1. local glucocorticoids
2. Light stabilizers
3. Light-hardening
4. Chloroquine (+ internal prednisolone)
5. Azathioprine (+ internal prednisolone)
6. Ciclosporin A. (+ internal prednisolone)

Light protection: Strict avoidance of UV radiation, including visible light if necessary (determination of the action spectrum by means of photoprovocation tests). Consistent textile and physical/chemical light protection (e.g. Anthelios, Eucerin Sun, see also light protection products), tinted lotions and/or make-up if necessary.

Avoid photosensitizing substances (carbamazepine, phenytoin, phenothiazines, hydrochlorothiazide, tetracyclines, quinidine, etc.), see Table 1.

Light-hardening: If light protection is not sufficient, a so-called light-hardening with a very cautious UVA dosage such as 0.1 J/cm2 (as a medium UVA dosage) or a PUVA therapy can be initiated.

In the first two weeks of light-hardening with PUVA therapy, a combination with glucocorticoids in a medium dosage(prednisolone: 40-80 mg/day) should be applied; afterwards, a rapid balancing should be carried out. In the course of the treatment, maintenance therapy can be carried out at 4-week intervals. In a long-term study, 20% of patients showed normalized photosensitivity after 10 years (!), 50% after 15 years.

Chloroquine: If light-hardening is unsuccessful, short-term therapy with chloroquine (e.g. Resochin) 250 mg once a day or hydroxychloroquine (e.g. Quensyl) 200 mg twice a day p.o.

Azathioprine/glucocorticoids: If necessary, also try immunosuppressive therapy with azathioprine 100 mg/kg bw/day p.o. in combination with glucocorticoids such as methylprednisolone (e.g. Urbason) 40-80 mg/day p.o. (maintenance dose 4-8 mg/day).

Ciclosporin A/glucocorticoids: trial of an immunosuppressive alternative with Ciclosporin A 1.5 mg/kg bw/day p.o. in combination with glucocorticoids such as methylprednisolone (e.g. Urbason: dosage as before)

Concomitant therapy: betacarotene (e.g. Carotaben Kps.) or nicotinamide (e.g. nicotinic acid amide 200 mg Jenapharm).

Photoallergenic substances

1. Angeletti F (2016) Actinic reticuloid. Act Dermatol 42: 482
2. Dawe RS et al. (2003) Diagnosis and treatment of chronic actinic dermatitis. Dermatol Ther 16: 45-51
3. Gramvussakis S et al. (2000) Chronic actinic dermatitis (photosensitivity dermatitis/actinic reticuloid syndrome): beneficial effect from hydroxyurea. Br J Dermatol 143: 1340
4. Ive FA, Magnus IA, Warin RP, Jones EW (1969) "Actinic reticuloid"; a chronic dermatosis associated with severe photosensitivity and the histological resemblance to lymphoma. Br J Dermatol 81: 469-485

5. Paek SY et al (2014) Chronic actinic dermatitis. Dermatol Clin 32:355-61, viii-ix.

6. Zak-Prelich M et al (1999) Actinic reticuloid. Int J Dermatol 38: 335-342